Have you experienced friend not responding after vent

I'm not the type of person to always vent to people so when I do, you can tell that what I'm going through really hurts. It was my first time venting to that friend (it wasn't out of nowhere, I looked hurt and cried irl too) and after sending a long message they left me on seen until I just decided to delete it. This happened twice, the only time they replied was when the long msg was about me comforting them for feeling things abt my situation. I looked it up before posting here and saw on quora that people who leave you on seen like that when you clearly need comfort or help are not really your friends because if they were they'd care enough to even offer words of comfort. So like... Idk.. I have no friends I can lean on for support rn at all because the person I'm having a fight with is pulling them all to her side (this person is diff from the one I'm venting to btw) I honestly don't know how she can laugh everyday knowing she's hurting me, when I've always been there for her even at her lowest reputation, when she was hated by everyone, when I was hated by others just bc I was friends with her, whenever she got sick I was the one who took care of her and assisted her, when she was depressed I was the one always by her side and accompanied her everywhere so that she won't feel alone. It's so clear that she doesn't care about me at all because how can you still give me the cold shoulder when you know you're hurting me this much? Btw our fight happened just because I suggested that she doesn't paint the board during our event festival because the paper she stuck on it already looked good and she got angry so she ripped it apart. Nonsensical right??Her reason is so fucking unjustifiable to the way she's treating me rn when all I did was make a suggestion she didn't like meanwhile I've always been there for her through everything.