It's a combination of the Women-are-wonderful Effect [0] (which goes double when it comes to sexuality) and the universal lack of giving-a-shit about problems that men face.
Men's sexuality is dangerous and unnecessary. Womens' sexuality is moral and precious. To say that womens' sexuality is causing a social problem is absolutely unacceptable in establishment cultural spaces.
The other side of it is that nobody cares about mens' problems. In this case, the "problem" is that men's standards will be distorted by AI girlfriends, which is bad... for women. We cannot say that womens' standards will be distorted by an AI boyfriends, because womens' standards are always appropriate and pure, and women always deserve what they demand. We cannot say that womens' AI boyfriends will cause loneliness among real men, because if a man can't perform well enough to attract a woman then his suffering is entirely his own fault and responsibility and nobody else's concern.
It's similar to the issue of men falling far behind in education. When there is a new article about women getting 60% of the degrees (3:2 ratio), it is always framed as a problem not for men, but for women, because now they can't find guys better-educated to marry. The idea that the men might deserve equal education for themselves isn't even worth considering, because men deserve nothing and their suffering scores zero on the moral-imperative scale. It only matters in how it affects women.
[0] https://en.wikipedia.org/wiki/Women-are-wonderful_effect