Interesting that you don't think the post acknowledged your second collection of points. I thought it mostly did.
1. The post did say it was not suggesting to shut down existing initiatives. So where people disagree on (for example) which evals to do, they can just do the ones they think are important and then both kinds get done. I think the post was identifying a third set of things we can do together, and this was not specific evals, but more about big narrative alliance when influencing large/important audiences. The post also suggested some other areas of collaboration, on policy and regulation, and some of these may relate to evals so there could be room for collaboration there, but I'd guess that more demand, funding, infrastructure for evals helps both kinds of evals.
2. Again I think the post addresses this issue: it talks about how there is this specific set of things the two groups can work on together that is both in their interest to do. It doesn't mean that all people from each group will only work on this new third thing (coalition building), but if a substantial number do, it'll help. I don't think the OP was suggesting a full merger of the groups. They acknowledge the 'personal and ethical problems with one another; [and say] that needn’t translate to political issues'. The call is specifically for political coalition building.
3. Again I don't think the OP is calling for a merger of the groups. They are calling for collaborating on something.
4. OK the post didn't do this that much, but I don't think every post needs to and I personally really liked that this one made its point so clearly. I would read a post which responds to this with some counterarguments with interest so maybe that implies I think it'd benefit from one too, but I wouldn't want a rule/social expectation that every post lists counterarguments as that can raise the barrier to entry for posting and people are free to comment in disagreements and write counter posts.
I don't think it's obvious that Google alone is the engine of competition here, it's hard to expect any company to simply do nothing if their core revenue generator is threatened (I'm not justifying them here), they're likely to try to compete rather than give up immediately and work on other ways to monetiz. It's interesting to note that it just happened to be the case that Google's core revenue generator (search) is a possible application area of one of the LLMs, the fastest progressing/most promising area of AI research right now. I don't think OpenAI pursued LLMs for this reason (to compete with Google), and instead pursued them because they're promising, but interesting to note that search and LLMs are both bets on language being the thing to bet on.
Why isn't anyone talking about the Israel-Gaza situation much on the EA Forum? I know it's a big time for AI, but I just read that number of Palestinian deaths, the vast majority of whom are innocent people, and 65% are women and children, is approaching the level of civilians killed in Ukraine since the Russian invasion 21 months ago; just in the last 3-4 weeks.