Capital punishment is not the issue. Two other issues are far more important in addressing concerns that Israel could become Talibanized. The first is that not everyone listens to Moshe Grylak – or his gemara. You can argue that the community should not be held responsible for the escapades of kano’im and Sikrikim – but they aren’t doing a very good job holding them in check either – or even speaking out against them. Why wouldn’t a chiloni Israel look at their activities with concern that as the Chareidi community grows, there will be more on these zealots, who will become even more brazen in time?
More important is the gemara that Rabbi Grylak does not quote: Rosh Hashanah 6, and elsewhere, which establishes the authority of the Jewish court to compel people to perform mitzvos. The plain meaning of the text is that people who are reluctant to perform mitzvos can be compelled through grievous bodily force to obey the law. Couple this with the authority of beis din to act le-afrushei me-issura/ to distance a potential sinner from his ability to sin, and you have a license for batei din to compel full observance of the Torah, both affirmative and proscriptive obligations. No witnesses, no forewarning, none of Rabbi Grylak’s niceties that calmed his secular friends. Why should they not anticipate groups of people jumping out of vans, forcing tefillin and tzitzis on their bodies, and bulldozing their soccer stadiums?