I'm not sure about how common. But plenty of lawyers practice in more than one area, so it's certainly not a problem to "switch" fields.
In terms of difficulty, I suppose it depends on how different the field you plan to switch to is. For example, I know a lawyer who started in personal injury and switched to employment after 10+ years doing personal injury without a problem. I also know a lawyer who started in employment and switched to family after 2 years of practice without a problem. Naturally there will be some learning curve but if you're a competent lawyer, you'll have enough basic skills to make the switch fairly easy.
Logistically, I think switching practice areas is even easier if you're working at a full-service firm. That way you have a reputation already for being a solid lawyer at the firm, you know the other lawyers in the group you want to join (hopefully), and maybe even had the chance to collaborate on files with them. In that case, as long as you get the go-ahead from management, you can basically just pack up your desk and head over to their group and start working. No need to network and go looking for a new place of employment.
I'm a 1L right now at UVic and when I picked the school I was a bit frightened I wouldn't be able to bond with my classmates because although I consider myself liberal I'm not that left leaning.
There definitely is a vocal minority over zoom and on the class social pages. However, everyone I'm friends with in person tends to have more of a moderate viewpoint. I really think there's a place for different viewpoints at UVic and I wouldn't want anyone to be turned off of the school because a few people are extra 'loud' with their opinions.
I'm sorry you're having that experience and not feeling particularly welcome GM! I think way more people than you think have the same perspective as you.