Yes and No. It's complicated.
Yes, it's harmful to my effeminate and queer non-traditionally masculine gay friends who endure ridicule, taunts, and teases from others throughout their lives. That can be traumatizing & damaging. There are a lot of children, teens, young men & older who have a lot of difficulty with these things and overcoming the way they're perceived and treated by others. (FTR I am masculine and assumed to be straight so do not have these problems, but I am very aware of them from my much gayer friends.) I can see why the APA considers traditional masculinity to be damaging.. even to masculine straight boys who aren't raised to be open about their emotions and such.
and No.. these traditional masculinity traits are what perpetuates the survival of our species via the age old cliche of "survival of the fittest." There's a reason we have evolved to behave this way, and while it's unpleasant for some of the "softer," folks out there, it's necessary that the "harder," ones stay strong, fit, and dominant in order for there to be safety and security for others, as well as to provide for them & theirs. No reason to be as*holes about things for no good reason, but there are plenty of reasons to be strong & firm about most things in life - especially when they pertain to obtaining & maintaining survival essentials like food, water, clothing, shelter, medicine etc. Can't be weak if you want to live.. and especially so if modern society collapses and the conveniences we're all so used to disappear. If and when that happens, the APA can take their "this is damaging," stuff and shove it while the weak die and the strong survive.
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No
for supporting trump. Because doing so is deplorable.