Instagram question

So I have a private Instagram, only because I don't want my psycho ex boyfriend to look at my page.

I keep getting follow requests from people I don't know. I look at their profiles and it is no one from my past and doesn't appear to be a BOT. Is there some kind of algorithm for Instagram users who are trying to gain followers by following random people? Like they just spam a bunch of people like myself? I'm just curious how these people are randomly finding my page. I'm not advertising a business or anything. I feel bad declining their follow. I'm just curious how it all works. I'm really boring anyway, not sure why they would want to follow me 😆

Thanks!

Also, not sure where to post this lol.