Yes.
It's only fair. I'm not saying its right to beat they ass if they don't but dont expect someone to favorably when you tell them after or they find out. Thats a dealbreaker for most folks.

It would be the right thing to do in a perfect world. Then again, so many transgender people get killed for their identity that I have no right to judge someone who was too scared to share their identity.

Might as well not mention that you have an STD while youre at it right?

because being trans is infectious and or deadly and is directly putting another person's health at risk if you have sex with them. Of course.

This is not really a problem for me as there are very few trans men who are attracted to men. However, I think they have the right not to tell them. After all, everyone has some secrets at the beggining of the relationship and not all cisgender women are able to give birth. There is a time in a relationship where you should, though, but it's definitely not important in a hookup or sth

Yes, I would feel hurt and taken advantage of if I was the guy in this situ.

Just because someone is trans, it doesn't stop them being a duplicitous liar or the situ excusable.

For hook-ups, no.

For long-term relationships I'd have to say yes. It doesn't have to be straight away and they shouldn't have to go into great detail if they don't want to, but if they're committed to someone, trust them and want to spend their life with them then yeah, they should tell them at some point.

I understand why transsexual people may be hesitant to do so - as not everyone would react to it well - but in all honesty if someone reacts badly they'd be better off without them anyway. It's a shame that it's even an issue, it wouldn't bother me at all.