So we'll assume that's all magically resolved. A vast fortune has been spent and the Meddlers' Conglomerate now has 40 million Ether. Just need to stake it and the blockchain's theirs now! Except there's another problem; Ethereum's staking contract has a rate limit on how fast Ether can enter or exit it. This was built into the system to smooth out any sudden shifts like this. The rate is 57600 Ether per day, so it'll take 694 days to finish moving those 40 million Ether into the staking contract. Almost 2 years.
Alright, it's been 2 years and now the Meddler's Conglomerate has moved their vast fortune into the staking contract. The whole world has been watching with bated breath, because there's no way that you could do anything like this secretly - the blockchain is an open book. Maybe somehow they've managed to keep their real-world identity secret (though people are perhaps wondering about the coincidence that Elon Musk, Jeff Bezos, and a couple of others are now drawing welfare cheques) but the pattern of activity on the staking contract is in the clear so everyone knows which staking accounts belong to this giant whale of a staker. Let's see what they do!
So they're rejecting certain transactions relating to the Reddit community point rollup. Note that there are ways you can write a rollup contract that would prevent the base layer from having any say in what goes on inside it, but let's assume that Reddit wrote it stupid and they're able to have some sort of impact. The rest of Ethereum's userbase nods, saying "aha, I figured they were probably up to no good." At which point they roll out a User-Activated Soft Fork for Ethereum that locks those 40 million Ether. There is nothing that stakers can do to prevent a user-activated soft fork from going into effect provided basically all the users want it to go into effect. It's a nuclear option, but the Meddler's Conglomerate started the nuclear war first and this will finish it. The Meddler's Conglomerate now owns zero Ether. They are broke. They probably didn't even manage to disrupt the blockchain much in the process, aside from making a bunch of cryptocurrency speculators insanely wealthy.
This scenario, "what if someone with infinite money wants to do something nefarious?", has been war-gamed and planned for in excruciating detail for nigh on a decade now. Ethereum's built a lot of very robust mechanisms to prevent it. And whenever a token or rollup spins up that's "on the Ethereum blockchain" they inherit all of that security.
So yeah, for all Reddit's faults and all that people might pooh-pooh "cryptobros", this actually is one of the better ideas they've had in a long time. It's more secure and more open than running it on their own in-house private database.