What gets me nervous is that if a seminary can ignore the countless gemaras which say that it is the derech of women to wear makeup, and that the father or husband must provide them, and that women are mechuyav to use them, then maybe we must be choshesh that they are trying to shmad girls to another religion. Remember that not all forms of apostasy are kulas. The tzeddukim or karraim believed that one cannot have any light burning all shabbos long because of the posuk lo sivaaru aish bchol moshvoseichem byom hashabbos. They also believed that a tvul yom could not prepare the parah adumah, but we are meikil. They were far more machmir than we are, yet they are apostates.
The next thing is that they will then not allow their young children to play with children from homes where the mother does use makeup because it is a bad influence.
It is a vicious cycle. The more chumras they invent, the more separation they need from those who don’t keep the new chumras. This then requires even more new chumras to prevent any contact between the groups.
Joseph, although you have numerous sources that makeup is the norm for Jewish women throughout the doros, and have one that possibly says it can be harmful when overdone, so you assur the entire concept? Food is also harmful when used to an excess. Even water can be fatal if one drinks too much. So you are going to assur these, now, as well?