Using tumblr as an example, I really would not be as opposed to it them using ActivityPub. Would I like it? No, but there are 2 things that make Tumblr different. The first is userbase, tumblr is nowhere near as large or mainstream so while it would still be a firehose of content, it wouldn’t be nearly as unmanageable as Meta. The second is, well, tumblr is a joke compared to Meta. Meta is literally a household name, they have shitloads more resources than tumblr does and has a much higher chance of being able to fuck our shit up.
Regarding your example with Valve and Linux, while I see the point you’re trying to make, I don’t think it’s quite the same. In this case, as you yourself say, Valve stands to make more money if Linux users are able to purchase and play their games. That is their incentive to help Linux, without one they just wouldn’t do it. Those actions aren’t bad either, they are good for Linux users.
This scenario is a bit more like if Microsoft announced that they were working to get the Office Suite built into the Linux Kernel itself. Some users welcome the change, after all, Office Suite is used everywhere, so maybe this will make Linux more accessible to some. But other users are pissed, because they could just use Windows if they wanted Office Suite built in, they chose Linux because it did not.
In this scenario, i’d be more inclined to side with the latter users. There are 2 seperate, distinct pieces of software, and some want one to be more like the other, instead of just using it themselves. I mean, it’s silly really. You can choose to use either platform, why force one to become the other?
I do see what you are saying and I think this point is really the only one that has any validity to it, because the idea of this thing is that it should be as open as possible. I would of course say Lemmy, Kbin, Mastodon, they should federate with one another despite being technically different sites.
But the issue doesn’t lay with Threads itself. Take Meta out of the equation and i’m up to federate with it. I think it might really change things with there suddenly have 10’s of millions of users suddenly here, but I couldn’t assume it would be for the worse.
The issue lies with the ruthlessness of the company itself, and its history of awful behavior. As soon as it becomes more profitable to screw over Lemmy (this will happen, you are always going to be more profitable if everyone is using your platform, plain and simple), they will. In my eyes it is not a matter of if, but when. Everyone at Meta involved with threads could have good intentions for it, I can’t say they don’t, but staff changes, and a company’s attitude towards projects shifts.
Meta has the resources to create whatever they want. They could develop something much more feature-rich than anyone could ever want, without ever involving or needing the Fediverse at all. They would own the entire thing, and would not need to deal with outside forces at all. So we have to ask ourselves, what do they look to gain from federating with us?