Bf always siding with other girls

Ok does this happen to anyone else...

So I talked to my bf about how my sister got bullied and of course he was really empathetic and worried about my sister.

Today I opened up about my friend who was actually a bully for the majority of my middle/high school self. And he sided with her and made excuses to why she was a bully. I’m glad he wants to play devils advocate and discover the reasons why she was mean to me but sometimes I just wish he was as empathetic towards me too.

He told me about his bullying experience and it’s like I’m not gonna go make excuses for his bullies (even if they have them) I listened and made sure he was ok.

This isn’t the first time like every issue I have with another girl he always sides with them 😭 maybe I should just talk to my girlfriends about these issues cause they would just be like “omg that bitch” lol which is all I need. To vent and be validated. If I’m in the wrong they would tell me also but always see my side too.

I feel like I’ve experienced this with other guys too. Is this common?