It is a very serious offense and therefore the punishment is serious. (BTW, many forbidden heterosexual acts, such as adultery, also are punishable by death.)

The stoning punishment is not carried out anymore, for technical reasons. Not only that, when it was carried out, it was only after the perpetrators were warned immediately before the act by two people that if they do it, they are liable the death penalty. Under such circumstances, capital punishment was very rarely performed.

In any case, what the Agudah rabbis said is perfectly in tune with the Torah, as indicated in the sources that I brought.