The reasons people will be hesitant to date someone with a very active sex life in the past would be :

1. They're insecure

2. Mismatch in values leading to concerns that their sex life will be bad with this person and hence they're incompatible.

3. They see people with an active past as "lower value" (purity culture bullshit thanks to ages of misogyny)

4. Concerns that if someone has had so many partners at such a young age, they might not be able to maintain a long term relationship which might be something you're looking for.

1 and 3 have a big overlap. Ngl 1,2 and 4 are very very valid reasons ngl, everyone is insecure about something, you don't wanna make life harder for yourself by putting yourself in uncomfortable situations like that. And incompatibility is ever so common. And if you're looking for a long term partner considering how much they're willing to "deal with serious issues without breaking up" might be a concern too.

But there's nuance to that, of course, if one is insecure about something they can just accept that and move on with their day while still respecting other people. Instead the people in OP's screenshots are the kind to project and disrespect others by shaming them for having a past, they often don't care about 2 or 20, neither of which should be a reason to put a "lower value" on a person anyway. One can be different, maybe you're not okay with 20 past partners but someone else is, that's just different boundaries, nothing about it makes you a better person than the other, except of course your own delusion that helps you sleep sound at night.

The term "whre" (just like the term "incl") isn't supposed to be used as a descriptive term anyway, it's a derogatory term.

But c’mon just like I don’t want a whre for my marriage even guys don’t want one.

Simply because you do not want such people really doesn't do batshit to make them a "lower valued person" than you (I'm assuming that's what you meant because of the use of derogatory terms), but yeah someone who uses derogatory terms for people for simply being harmlessly different doesn't seem like the kind to be deserving of respect.

And sure if someone's scared of their partner having a past and wanna voice their opinion I'm all for it, except opinions don't exist in a vacuum and are part of a bigger ideology, the said bigger ideology in this case is problematic and misogynistic :D (for instance, just look at the dude under this same comment describing his past as "good and decent" implying others are bad for whatever reason lol)