Yes, but this study isn't replacing the entire biome. What I was citing, was a case of people having lost their gut bacteria completely. They use a relative, as using a random person in such cases, which isn't a match for that person's genetic history, can be quite harmful.

It's precisely why they seek a close relative.

Adding some additional gut bacteria doesn't replace everything you have. Otherwise, you'd get sick from eating a salad someone else prepared, and ingesting some of their bacteria. The peanut thing may be introducing an additional bacterium which perhaps processes peanuts in a better fashion, but without supplanting anything?

So I won't say you're wrong. But without trials I won't say you're right, either.