Any normal man would read the above as nothing other than an insult, not to his masculinity mind you, but to healthy sexuality and overall integrity. This Viressa person basically says "if you don't like to get pegged, it means you're scared and insecure", and that is fucking insulting no matter how you try to sugarcoat it.
On this comment, to minimize the back and forth and speed up the process, I didn't interpret the pegging fetish comment as an insult, only another fantasy of another person, so am I not a "normal man"? Am I another freak? Jk
Either way, to address what you wrote, when we look at it logically, that's not the correct summary of the comment, it's also not logical to conclude that the comment constitutes an attack on men in general. It's basically saying that the first pegging is often full of vulnerability, perhaps on the part of the man, because many societal forces have convinced straight men and boys that having something up your butt for pleasure is unmasculine, so many people, including the men themselves, will internalize that and associate pegging with emasculation, which straight men are often afraid of. It's OP's opinion on good character work, being pegged consensually won't take away your sexuality and integrity, it just means that someone pegged you with your agreement.
Now of course, this is also contingent on the presupposition that the pegging which the original commenter described is consensual, because otherwise would be rape, and that would change the entire premise of this conversation.
So to make this short, from my point of view, it's not "If you don't like to get pegged, it means you're scared and insecure", it's "the first pegging will usually be accompanied by vulnerability, and that vulnerability is where good erotica is written"
Folks are making mountains out of molehills too much these days, it's like how conservatives take Starbuck saying "Happy Holiday" as an assault on Christianity or Leftists being offended that Jordan Peterson might deliver speeches on their campuses, next thing you know, people might cry on the spot if you so much as disagree with them.
And I must also attach a disclaimer, I am a man, but I'm not straight, so my perspectives differ significantly to my straighter counterparts