I didn't say all masculinity is toxic. I think masculinity is fine but then you have things like this:

"Man up"

"Boys will be boys"

"You throw like a girl"/"[blank] is for girls"

"When men were men..."

"No means yes, yes means anal"

You can't deny there are some really terrible behaviours and expectations that have been normalised in our culture and they are considered as being inherent to masculinity.

No, toxicity is generally determined by dosage of a particular toxin, not grouped by toxins and non-toxins (example: water). This definition holds here too.

It implies that too much of a thing can be dangerous which isn't always the case.

It is a loaded term. It doesn't belong here, anymore than announcing women are all bitches belongs in civil discourse.