FtM: feminine and masculine

I’ve been trying to understand this for a while. Im looking for explanation to help me understand this within the trans community as a whole, but specifically in the FtM community.

As a trans guy, I want to pass as a cis male. I try not do anything that would call attention to my gender, such as wearing makeup when I clearly present as male. I use he/him pronouns, and I carry myself as more masculine. I’ve always had this mindset pre-T and even after starting T.

When I come across other trans guy in the world, who happen to be very out and proud (props to you), they have a different mindset than me when it comes to masculinity. Many (not all) still act very feminine. But they identify as male. They don’t identify as trans-masc, or non-binary, or queer, etc. They identify as a trans man and use he/him pronouns only. Many of them also tend to not pass as well physically and can be mistaken as a female/woman. So this makes it harder for them to pass physically.

So my question is, if someone identifies as a trans man and use he/him pronouns, why don’t they carry themselves in a more masculine way?