"Apparently my headphones make me invisible at work"

I work in a pretty casual office where most people listen to music or podcasts while they work. I am one of maybe three women in a team of about 20. I keep my big over-ear headphones on a lot because open office + constant chatter = no way my brain will focus otherwise. Lately I started noticing a pattern that is honestly kind of freaking me out.

If one of the guys has headphones on and someone needs something, they gently wave, maybe tap the desk, wait for him to pause his song. With me, they just start talking at full volume while I am clearly zoned out, or even worse, they walk around me to ask the male coworker sitting behind me about the project that I am literally leading. Stuff like "hey do you know where SHE is with that report" while I am right there. I have had men lean over my chair, read my screen without asking and then go "oh ok so you are on it" like I am some kind of shared computer, not a person.

Last week I tested something. I took my headphones off for a day and just kept them around my neck. Suddenly people were making eye contact, asking me direct questions, even waiting for me to finish typing before interrupting. Same outfit, same hair, same tasks. The only difference was that I looked more "available" I guess. I am trying to figure out if I am overreacting or if this is that subtle office sexism where womens focus is always seen as less important. Part of me wants to call it out, another part is tired of being the one who always has to explain basic respect .