Why is Ripple's controversy relevant to Stellar? As I understand it (and I may be wrong, I was not aware of Ripple until Stellar), the big issue was that the founders of Ripple Labs allocated 20% of all XPR to themselves.

Stellar, on the other hand, is only holding 5% of STR in reserve, which is used to fund the nonprofit, and already sold off 2% of that to Stripe (who in turn is going to be auctioning off 50% of that). Ripple's approach looked like a pre-mined altcoin thing, but Stellar has a significantly smaller reserve that's very publicly being used to fund the operations of a nonprofit, rather than being used to enrich 3 individuals.

Basically the only odd thing here is that using STR as a source of funding means that they care about the market value of STR, whereas most uses of Stellar don't care at all about the market value of STR but only use it as a medium of exchange. That said, all the Stellar Foundation really wants is for STR to remain relatively stable (which it should), whereas with Ripple's approach there's a genuine conflict of interest as the founders would get personally rich if they could boost the value of XRP (conflict of interest because it's in the network's best interest for XRP to remain stable, just as STR is expected to remain largely stable).

That was one issue. Another is that the consensus protocol did not work in practice, at least not decentralised. The obvious problems were hand waved away with a promise to solve them later.

Another was that the open source software was not delivered on time and did not live up to expectations, especially not given the above. If Ripple the company went under, so did the network, and that is not really acceptable for a trustless distributed global currency.

Has Stellar addressed any of this or are we just supposed to trust them?

Ripple (and therefore Stellar, the hostile fork) is not decentralized, at all. The underlying protocol does not work in an adversarial, decentralized context.

I used to be afraid that this is so since it seemed for a long time that only one server exits. But now there are many gateways so there are many node in the p2p network. So how is this not decentralized? And, since there is money involved, there seems to be high incentive for adversaries. So it seems Ripple does work in an adversarial, decentralized context. What am I missing?

I am honestly interested in this. I have trouble finding any reliable information about the viability of the Ripple consensus mechanism.

Stellar is a direct fork of Ripple, with basically zero significant changes.

I can't speak for others, but for me the politics, not the technology, of Ripple was always what I had an issue with.

The bad technology is what facilitated the bad politics.

Ripple started out with really nice-sounding politics, but because the tech is centralized, all the nice promises were promptly violated. There is no reason the same won't happen here.

There was also some concern that the "automatic liquidity provider" feature of Ripple was dangerous, but it sounds like Stellar may disable that.