I know quite a few people who aren't in tech who live in the area and quite a few people who work there. I live nearby and hang out in Venice Beach a decent amount. I even participated in the protest that was out for two days on Market street and talked to a good number of the other protesters. I have my very specific viewpoints of why the protest was good but I find flaw in what you've written and what I hear from many of the other protesters.
Your main point seems to be the office space they use. Can you give me one example - just one - of some previous tenant of a Snap building who was actually evicted against their will? I've talked to a guy who is the property manager for a good bit of that area and he says that for all of the properties that he knows of, the previous tenants were moving out on their own and Snap was just the company to take over the unit.
You also seem to be missing the answer to the question of why it matters that they take over these "luxury private living spaces." I've heard answers from locals that I can see their perspective, even if I don't agree with it, but they are attacking the other office space that Snap uses. I'm curious why you focused on their "luxury" apartments.
(hint about the previous two paragraphs - I think that there's an issue with their space, you just seem to be missing what the issue actually is and how to prove it)
As a tech worker from SF I've seen what real protesting is and what real gentrification is. If all that the protesters in Venice can do is a few dozen people for two days that's not going to ever have an effect.
The primary gentrifying force in the area is simply that it's getting cleaner and nicer and you can't have beachfront property in LA (especially next to Santa Monica) without it getting popular. The only thing keeping it cheap was that it wasn't that well taken care of. While Snapchat may be an easy face to blame things on they're not the main thing causing the change in the area. The change would happen whether or not they were there.
Petty crime and other issues in the area surrounding Snap's buildings has supposedly halved since they moved in (secondhand source from someone claiming to hear it from a local cop - I believe exact words were "calls to the area have dropped 47%") due to their security force patrolling the area. This is actually a huge point - every local I talk to that is positive towards Snapchat sites how much cleaner the area between Rose and Market along Speedway/Ocean Front Walk is now that Snap is there.
Their security is actually one of my concerns since I think their security is a little too over the top. I've seen them tell people to move who are just hanging around what should be public areas but near Snap buildings. It gives the block a vibe that these tech workers need to be protected from the rest of us dirty, dangerous people. I've actually had the chance to talk to a couple of the guards - they agree with me on this point. If it were up to them, they would only be inside the doors of buildings. They have plenty of security camera coverage of the area, which combined with plainclothes patrols would be plenty to keep their area safe.
Finally, you've already won! Snapchat was started by a Santa Monica native trying to build close to home and they've already realized that the area isn't really able to support the company anymore, according to what I've heard. It's publicly known that they've gotten the lease to nearly 400,000 sq ft of space at Santa Monica Airport. The rumor is that they're moving out of spaces along the boardwalk as their leases end, with at least one building already vacated. However, I'm not sure whether I totally believe that since their public mission statements note that they put value in having the "ocean front culture", though obviously they're probably paying a ton more per sq ft for the ocean front than the airport. Also I know these companies often get super long leases so "end of lease" may not even be that soon.