Why not? Someone being gay changes my views on them. Just like someone being vegetarian or religious or atheist, black or white, male or female, or almost anything changes my views on them in some way. What you should say is that it doesn't change your views on them for the negative.
There are many different scenarios:
A:"Do you know NPH?"
B: "No."
A: "Oh. He's gay and is adopting a son with his partner."
B: "Cool."
B: *watches NPH TV show or movie* "Hmmm, I like this guy."
No views "change" on NPH for B.
"Do you know NPH?"
"Yeah! I love in HIMYM and Harold and Kumar. I haven't seen Doogie Howser, though."
"Oh, it's a great show. I just read he was gay and just adopted a boy with his partner."
"Fuck that fucking faggot! I'm not watching HIMYM anymore! Not even gonna give Doogie Howser a shot either. Time to find a new actor to like to take his gay-ass spot."
Views changed.
In an alternate universe, the previous scenario could have also ended with "Oh, that's great for him and his partner. I'll give Doogie a shot too (completely unrelated to NPH being gay or straight)."
Whenever I meet a vegan, the few that I've met, I immediately think of (no offense) Casey's posts on here and how I feel it's propaganda to get us to switch too. So I approach them with the mindset that I could very well be talking to another Casey, just in real life. I have to slowly gauge how "eager" this vegan is to impose his views on me. Will he merely inform me of the benefits, or will he attack my personal eating habits and marinade me in news articles? There's a difference. But this would be stereotyping, right?
Similarly, some black friends can take a black joke, no matter how bad it is (and I've gone the whole nine yards after slowly testing the waters). Then there are some others that get offended very easily. But "testing the waters" draws something from stereotypes, right? And isn't stereotyping bad? Then why wouldn't you approach every person as a blank slate, no matter how much of their views the divulge? A lesbian Muslim transgendered woman that votes Republican? Can you honestly talk to that person without drawing upon stereotypes of lesbians, Muslims, and Republicans?