When is a forced act considered volitional?

Meshech Chochma(Shemos 19:17): And they camped under the mountain – this teaches us that the mountain was held over their head to force them to accept the Torah (Shabbos 88a). The mountain is a metaphor meaning that G‑d showed them His glory so clearly and forcefully that their natural free‑will was actually nullified and their souls departed from them as a result of the experience. They were forced to do the right thing - exactly as the angels. They saw without any doubt that the existence of all creation is dependent on the acceptance of Torah. (Rava even notes (Shabbos 88a) that because they had no free‑will when they accepted the Torah this provides a justification to not keep the Torah.) Similarly if a person is pressured to bring a sacrifice until he says, “I want to” (Rosh HaShanna 6a) it is considered a voluntary act. The explanation of why a forced act is considered volitional is given by the Rambam (Hilchos Geirushin 2:20): “We don’t consider an act forced except when a person is forced to do something which is not required by the Torah. But if a person is overcome by his yetzer harah to nullify a mitzva or to do a sin – and then he is beaten until he does the mitzva or avoids the sin – this is not considered that he has been forced to act. But rather he is viewed as originally having been forced by his yetzer harah to do evil… But since he really wants to be a Jew and really wants to do all the mitzvos but is prevented from his evil inclination – by beating him it weakens his yetzer harah so that he can do the right thing…” This is a wonderful analysis and is consistent with what he says in Hilchos Sanhedrin that if a person is forced to have sexual relations where the law requires him to die and not transgress and nevertheless he transgresses – he is liable to the death penalty since he can not get aroused without being interested. In contrast the Rambam notes in Hilchos Yesodei HaTorah that in a situation where he is required to die rather than transgress and yet he transgresses - he is not liable for that sin. Nevertheless he has transgressed the mitzva of sanctifying G‑d name. The explanation for this apparent inconsistency is that all the sins - such as profaning Shabbos or idolatry - if a person does them because he was forced this is not considered to be a voluntary act but rather it was only because of the force and there was not inner desire to sin. However in contrast concerning sexual prohibitions, the man does not get aroused because of the fear of punishment but only because of his lust for sexual intercourse. Therefore he has the ability to restrain his lusts and not get aroused. Thus if he does get aroused it is because he wants to get aroused. Consequently the Rambam asserts that a man’s involvement in sexual sins can only be a willful act and because of this he is liable – even though he was pressured to do it. So even though he only gets aroused because the fear of punishment cancels his fear of G‑d and is now left with his natural lust for sexual intercourse, which is like his lust for his wife – nonetheless this is still called a willful act. The natural desire of a Jew is the inherent desire to fulfill G‑d’s mitzvos. It is only the advice of the yetzer harah (evil inclination) that prevents him from observing the mitzvos. However when he is severely beaten this removes his physical lusts, which had prevented him acting, and he now does the right thing e.g., divorcing his wife or bringing the sacrifice or accepting the Torah. Since he is acting in according with his true inner desires it is considered a fully willful act. However the Ramban (Yevamos 53b) disagrees with this idea that when force removes an impediment to a natural desire it is called a volitional act. The case he discusses involves a man being forced to have intercourse. The Ramban says that when the man is threatened by force to have intercourse - it is not a volitional act. The force causes him to focus exclusively on the lust and not the fact that he is sinning. By removing his awareness of sin it takes away his free‑will so he is exempt from punishment. So too in the case of the forced divorce or forced giving of a sacrifice or the forced acceptance of the Torah at Sinai - they would also not be considered a volitional act. Therefore it is clear according to the Ramban that when a man is forced into intimate contact with a woman – but not threatened – he still has the free‑will not to get aroused. This is different than a raped woman who we say is forced by her aroused lust even to say she wanted the intercourse (Kesubos 51b)… [However we are left with a problem. If the force at Sinai did not result in a volitional act of acceptance, why should the Jews have been punished for sin such as with the destruction of the First Temple which resulted from idolatry, murder and sexual prohibitions?] According to view of the Rambam a child who converts is able to protest against the conversion when he grows up. However even if he stops being a Jew he still remains a ger toshav. The Ohr Someach (Hilchos Issurei Bi’ah 12:6) explains that in the case of Sinari - as the gemora points out – they had a valid excuse not to keep the Torah because they had been forced. Nevertheless they would still be considered as ger toshav. That is the reason that in the First Temple they were punished for idolatry, murder and violating sexual prohibitions. Even though they were not technical obligated to keep the Torah as Jews, nevertheless they had the status of ger toshav. It wasn’t until the time of Mordechai and Esther - which was after the destruction of the First Temple - when they fully accepted the Torah of their own volition.