Unless you decide to attend a college/university that has a conservative bent, you will find that the vast majority of institutions of higher education are populated with liberal faculty and liberal students. Bryn Mawr isn’t all that different. As for academics, faculty should treat you professionally and base assessments on academic performance. BMC is small enough that you can spend time conversing with faculty members, especially with your Dean and engage in debate/conversation/questioning. That access to faculty is one if the pluses of being at a small LAC.
My D is a BMC grad and was also the equivalent of an RA–she was always willing to offer the kids on her floor assistance on finding their people/groups on campus.
You can make your college experience what you want it to be–there are ways to do this. My D’s roommate was a political science major. She spent a semester in DC as an intern and also spent a semester in Argentina. While that is an anecdotal example–it does suggest political science students have options/opportunities for internships and outside of campus studies.
Did you visit BMC? What attracted you to the school in the first place? If you are admitted or already have been, you need to go to admitted students days and see if you can find the environment that you are seeking. Talk to faculty and students and then decide for yourself.