I'm fine with being "checked out," and fail to see any reason to not be. No harm or ill will can come from looking unless it's in person and the looker crosses the line into being obnoxious with their ogling. That's not a gay/straight thing, though. Men and women can do that to one another just the same.
The same principle applies with compliments. No skin off my nose if a gay guy wants to say something complimentary about my physical appearance. A compliment is a compliment. I don't at all mind guys on here critiquing my junk. There is a difference, though, between someone telling me, "your [body part] is [adjective]" and them overtly telling me what they'd like to do with it.