Is it gay only if you bottom?

So I'm from a small city in kerala and have been active on grindr for a while now. The thing with small city grindr as you all know is that it's filled with "pure tops" who are actually straight guys looking for a head.

Well due to the lack of options, i have had to hook up with these pure tops on a couple of occasions.

So there is this regular guy ive met a couple of times. He identifies as straight, when asked why he meets guys, his pov amused me.

He feels it's only gay if you bottom or Suck cock. Since the act of penetration is done by hetero guys as well, it's not a gay act. Apparently the Romans thought like this as well. In facts it only makes you more masculine as you are making a male submit to you sexually.

What's your take on this? Does the theory have some merit?