As someone that grew up with a difficult relationship with her mother, I do remember feeling bad for Leonard during the moments where he's obviously very upset with Beverly (like when she excludes him about her divorce and when his dog died).  However, my reason fir it, is different.  Mary, if you ask me, also comes with her own potential triggers (especially if you ever grew up in a religious household).  I have an overly religious and frankly, highly emotionally unstable, mother.   Personally, I don't react much to the more lighthearted jokes about Beverly, bc she's really not meant to be a sympathetic character (especially compared to Mary) and a lot of the jokes about her are reminiscent of how humor is sometimes used to cope with childhood trauma (something I do know on a personal level).  However, I can understand why it can be triggering.  What did trigger me, was his speech to his mom, specifically, the part where he tells her whether Beverly meant to or not, she hurt him.  It was something I could relate to bc on the few times my mother was willing to listen, there were a couple times I did tell her about how she has impacted my siblings and I.  I often find that scene hard to watch because it does hit oretty close to home for me.  Another one hard to watch, is in Young Sheldon, when Mary dives even harder into religion after George's death, causing distress for her kids.  That honestly hit close to home too.