Being a binary, passable, post op trans woman, I cannot directly identify with your experience. However, there are many echoes in my encounters with “straight“ cis men on sites other than Grindr. There is no question there is a certain amount of fetishism involved. That does not really bother me. Being comfortable with who and what I am, I find it more amusing than anything. But you would be amazed at the number of times that I have started a conversation with a cis man who thought I cute and was later disappointed that I did not have a penis for him to suck off. That frequently put a quick end to a budding relationship. It is far more common than many people would likely think.
I fully appreciate the fact that those of us who are trans (no matter how we might identify individually) are viewed as exotic creatures. We are considered a kind of unicorn that appeals to many who are looking for something new and different. The ironic thing to me is how many of those who would consider dating me consider themselves straight heterosexual, cis men. Obviously, they are not. They may be confused about their sexuality and identity, but I am not. The whole thing I find quite amusing and entertaining to be quite honest.
Fortunately, there are those who (knowing my background, since I never hide it), treat me as a woman and are looking for a more traditional heterosexual kind of relationship. Since I am a woman, not a special class of woman, this feels natural and comfortable to me. I try not to take any offense from the chasers. In a perverse kind of way, it is actually somewhat affirming. At least they do not view me as a man, even if they haven’t quite decided what I actually am. In the meantime, I am thoroughly entertained by the variety of encounters I have and watching guys go through mental gymnastics, twisting themselves into pretzels when they are confused and not entirely forthcoming as to what they really want.
I can understand how you would feel uncomfortable in some of the encounters you have had. There is definitely an undercurrent of transphobia, or at least gender confusion, exhibited during your conversations, which can raise severe questions as to what the guys are really looking for and whether they are being honest. The way I handle it is with a somewhat irreverent sense of humor where I suggestively tease them a bit (I am not shy) to get them intrigued until they reach a point where they are being honest about what they are really looking for. That is when it becomes clear as to whether the relationship potentially has a future. I also never meet with anyone privately based solely on online communications. I always spend time with them in a very public place until I reach a point where I am comfortable and can verify that what I thought I observed is in fact true. It works for me, though it may not for you or other people. You asked for observations, so this is a reflection of my own experience.