It's a damned if you do damned if you don't the fans you're speaking of are Netorare fans, they get off on tropes like coming home and catching her actively fucking a guy, or voluntarily giving into cukoldry. Female MC does not provide them the core experience of what NTR is so if you tag it NTR now they are seeing a bunch of games in their tag they don't want to see, and as a fan of the pregnancy tag I get it, people like to throw games were 1 scene has her get impregnated and then literally nothing else and call it pregnancy and it's irritating wasting my time like that because unlike you where you click the thread realize it's ntr and immediately fuck off. People in this situation often get baited into downloading the game, wasting god knows how much time before they realize their tag isn't actually there. For the Female MC ntr people it's atleast slightly more obvious but it is a point of why to go this way than the other way.
While I agree with the base point you're making, I disagree with the baited part for NTR specifically.
Obviously the pregnancy tag is harder to figure out, so I can absolutely understand your frustration on that front. Think the game revolves around it, end up seeing a single cut away scene for the entire game at best that doesn't even involve the character you play as.
But where I find myself disagreeing is the simple fix to all NTR enjoyers: Search by tags and exclude "male protag" or "female protag". It's a magical cheat code that fixes 99% of the problem. Obviously, some still slip through the cracks, like games that make you play both perspectives and thus have both tags.
It's what I've been doing and worked out perfectly so far. I don't see why it's so complicated for so many, maybe because I simply don't enjoy male perspective for NTR and my encounters don't ever make it complicated?
But also, I don't look for NTR actively, I simply don't exclude it, so what do I know?
I believe instead of complaining what NTR is, isn't, should be or shouldn't be, it's much easier to just filter out the perspective you don't want to see. Feel free to disagree.