Toxic masculinity as commonly used outside academia is very amorphous concept. It's more like a "green" car than an electric one. We all more or less agree that some cars are environmentally friendly and some aren't, but not where the dividing line is.
If toxic masculinity encompasses a big chunk of masculinity, if there's no clear definition of non-toxic masculinity that's actually masculine, and if toxic femininity isn't ever discussed, it can seem like masculinity is considered to be an overall toxic trait while femininity isn't.
I think the GP was responding to the broader idea that masculinity is especially toxic in comparison to everything else, rather than the narrow "some men light themselves on fire to prove they're macho and get hurt, and that's bad" defensible academic usage.