This post was originally about Reform rabbis who were intermarried. The comment was made that there are also intermarried Orthodox Rabbis. This resulted in the following question: While it is true that if someone converts for the sake of marriage but they promise to keep mitzvos - the conversion is valid. However if someone questions the sincerity of a conversion for marriage - are they to be cursed? Have they committed an aveira? Rav Sherman said that Rabbi Druckman's converts were questionable. Did he have the right or ability to make such a statement? In our case - in which the future wives of Orthodox rabbis converted and the mikve ladies refused to supervise the tevila - it was reported that Rav O. Yosef and Rav Shmueli both cursed the mikve ladies. What prohibitions were these women accused of violating?
In sum, to what degree do people have the right or ability to question the validity of converts or even Jews? What manifestations of this doubt are legitimate. For example do you have the right to refuse to eat the food the converts prepare? Do you have to count them for a minyan?
You might remember a while back there was a Lakewood avreich whose Judaism was questioned - and it turned out he wasn't Jewish. Apparently those who raised the question committed no sin. I recently heard of a case where a woman was married as a Jew - not a convert and she lived for a number of years in the community had several kids and then her Jewish status was questioned by members of the community including a rabbi. Latest I heard the beis din asked to certify her as Jewish - has not found sufficient evidence that she is a Jew. None of the rabbis that I talked with have said that it was prohibited to question her status as a Jew.
Because these are current concerns - I am making this a separate post