OP, that sounds like a very toxic team if it's a real situation and you're not just trolling or very paranoid. Surely you don't try to talk politics or religion in the office, because that's just asking to have your head put on a chopping block. Maybe now talking about social justice matters and vaccination issues are topics to avoid, but those fall under the political umbrella. Another topic I like to avoid is 2A, although most of my teammates are pew pew owners. None of them, at least to my knowledge, felt so strongly about 2A that they'd bring a pew pew to the office. If they carried, they left it locked in their cars and never said a word about having it on Cisco property, which is what anyone should do if they're going to violate Cisco policy.
I've been on 3 teams at Cisco and none have been like what you describe. My current team has moved into the same BU that I was originally part of from back in the early 2000's when Chambers liked to say we're a family. I was impressed by the number of people at an all-hands in-person event that had a catered social hour afterwards that came up to me to catch up on old times. We haven't talked/emailed in years because our paths or work hasn't caused us to need to interact.
My middle team would message out that we were going to lunch every day & all who were free & wanted to go would meet in the lobby and we'd decide where we were going that day. Once there, we'd talk sports, current events, and stuff we were doing the next weekend. About 1/3 of the team was cyclists, so we'd talk about upcoming ride events and see how many of us to could participate to see if we could get a Cisco sponsorship to pay the entry fees, or plan an after work/weekend training ride to get ready for events, etc.
My current team is completely remote, even before the pandemic sent everyone out of the offices. Yes, we're not "friends" in the sense that we hang out together after work, but we're friendly in that we are willing to cover for each other if someone is out sick, on PTO, is having a family emergency, etc. We know that when we need to be away for several days, someone will go the extra mile to handle issues so no one has to reach out and ask us about work issues while we're out. It's certainly not the back-stabbing env that you describe.
Have I met individuals I didn't like? Were there people that have said things, in person or via email, that I felt were inappropriate for work? Are there people who don't like me? Yes, yes, and yes. But I've never experience feeling what you're describing.
The majority of Cisco employees and contractors are just that, people who work at the same company I do. A group of 100-200 people are what I'd call co-workers that I deal with on a recurring basis, be it once a year or once a day and they're just that, co-workers. Then there's my team and the teams that I deal closely with on a regular basis who are more than co-workers, but I still wouldn't call them "friends". They're more associates and peers and we have a fair amount of respect for each other. Then there's the few people on my team, or people that I've met through whatever interaction that are friends because we have common beliefs or interests. Like I said, I bike so there's that group. I like Anime & know some people who cosplay, so we've become friends. There's people that like to DIY or work on cars, so we've become friendly enough to share tips and/or tools, or help each other out on difficult projects.
You can make friends, and enemies, at Cisco, like any other company. It just depends on how personable you are. I think many people who were more introverted before the office shutdown have just stopped trying to pretend to be extraverted and just want people to give them space and leave them alone. As an extravert, as you can tell by this very long reply, I have to respect their wishes. Anyone who doesn't give a sh-t about this probably didn't read this far, and that's ok.