I use social media for business / branding, but not for pleasure or personal reasons.
What I have found is people are downright nasty to each other and will go out of their way to put others down for no reason. The amount of hate and negativity people have is stunning.
Don't take it personally. Best thing you could do is treat them with kindness. Don't engage and feed the negativity because that's what they sometimes want and all it does is keep the cycle of negativity going.
On my business facebook page, I once had a guy comment on one of pics saying "spiking a prune, get the fuck off" and another lady who commented on a pic of hedge trimming / pruning and said something along the lines of it was a good "DIY project where people could save a lot money" in other words hinting that people should do the work themselves and not pay a professional to trim their trees and these are people who I've never met! I wasn't spiking a prune by the way, I had a foot ascender on. So I politely responded to the person pointing that out in a professional manner, and they never responded.
That's one of the things you have to prepare yourself for if you advertise on social media as part of your marketing is the potential for bullshit, negative comments of people who see your advertising.
I really wonder why people feel the need to say some of the hurtful things they do to others on social media versus just saying nothing at all if they have nothing good to say. It really is sad, and consider how that impacts people's self-esteem, mindset, depression, etc. especially young people, kids, teenagers.