Facebook Account discrimination/ Algorithms or Human?

Hello!
In my Facebook account, the ability to add friends has disappeared. Not for all people, but only for some. To test this version, I logged into a second account. And on the other account, the "Add Friend" buttons appeared for the same people.
My version: So, it turns out that the Facebook system decides for itself who I can send requests to and who I can't (display the "Add Friend" button for me or not). If a certain parameter\filter matches the parameter of a person's profile, then the "Add to friends" button will be inactive for me.
There were no notifications of blocking certain account functions. So, all of this happened secretly and covertly.
I wrote to support, but they did not respond to me
What is the problem?
Screenshots from different accounts:

I think that this is part of the Facebook storm.

Facebook is scanning fake accounts and suspending them in order to stop spam.

My 5 Facebook aged accounts with no spam were suspended in this storm.

Maybe they're too busy.

I think it's random, due to accounts, some are supported and some are not

Facebook support is something that we just wait for luck

Waiting for Facebook's support team will take a lot of time