I see this sentiment all the time and it always bothered me, but I only recently realized exactly why: you're not talking about the same thing as the cis straight guys.
You don't have to be that attractive to find love. Plenty of ugly people have relationships. Just be yourself, dress well, don't say stupid things etc then go out and meet people and you'll probably meet someone you vibe with. But that's not really what the cis straight guys are talking about. They want to put less effort into having a sex life. They want to walk into a party and have women approach them. They want to feel conventionally attractive. Best way to do that is to be somewhat muscular.
Another less serious thing: backing up the "girls don't need muscle hunks" with pictures of a bunch of famous actors, several of which are definitely jacked, is not proving the point you want it to.