The question was NOT whether it spreads information from the articles to people who wouldn't have paid for it. The question was whether it suppresses sales of the articles to people who otherwise might have paid for it.

That's a more complicated question of fact. Some people now read Wikipedia and won't buy the article. Some people encounter the reference on Wikipedia and decide to buy the article. Which happens more?

I don't have data. But publishers do. And https://scholarlykitchen.sspnet.org/2022/11/01/guest-post-wi... shows what publishers concluded.

Publishers concluded that Wikipedia references are good for sales. And so jumped on the chance to cooperate with https://wikipedialibrary.wmflabs.org/. Which is therefore able to give free access to 90% of subscription only databases to you if you can prove that you're the kind of person who is likely to add citations to Wikipedia.

Legal questions are funny like that. You have to answer the question actually asked. If you merely answer another one that sounds similar to you, your answer is generally wrong.