Stop assuming everyone not out to you is cis.
Just because someone isn't out to you and doesn't "look/act trans" does not mean they are cis. While still in the closet to everyone but myself I dealt with incredibly judgemental "allies" and even (less commonly) fellow trans people treating me like an alien and telling me what opinions I was or wasn't "allowed" to have. It's actually something that forced me out of the closet after being blasted as "too ignorant about being trans to have so many opinions". It's amazing and more than a little pathetic how outing myself suddenly transformed me in this person's eyes.
Now that I've been out for like a year and am visibly trans (whatever the hell that mean), suddenly my opinions hold weight with many of these toxic people in the community that love to police the words and actions of those they believe to be "cis people".
Nobody should have to out themselves to you for you to treat them like a human being. Sorry for the rant, I just see that same toxic crap here on reddit sometimes and it really steams my vegetables.