Please don't lie about your past

I keep hearing from women that if a man cares about your past that's a red flag and you'd run. So like... please live by that. Don't lie to me. Why do that anyway? If it's so upsetting to you that I would care then why the hell would you go through the trouble of lying to me to keep the relationship going?

Another 3 months down the drain. I was casual but clear about this being important to me early on. This is the third time a woman lies to me point blank when I ask early on. And only once did a woman make it clear that she didn't think I should care. That was nice. We were incompatible and that was that. No time wasted. Please do that. In any case, if you're going to answer the question, do NOT lie. Be honest. Basic human decency.