First, I'm sure recruiting is involved. If you have to dump your citizenship at the same time, then I see a problem unless you have no allegiance for your current country of citizenship. Then, it's simply a transactional decision.
Of course, I believe that many use dual citizenship to solve that problem though I'm not up on the legal subtleties. I can't see a justification for doing it in Tennis, since there are so many other opportunities for competition.
But again, if you want to get into the Olympics and have the option, I guess it's a sponsorship paycheck if you win a medal and you weren't exceptional in professional play.
We are looking at this situation because of the ice skater. Not winning, I wonder how she feels about it now? I'm interested in seeing the final outcome for her. I didn't watch the Olympics but read about the skater in the news. I suppose it's about the USA vs China narrative in the media.
As for the bobsledder that switched from Canada to the USA, I'll have to find out about that and see if that bobsledder had to renounce their citizenship or have a dual one.
There there was Naomi Osaka. To me, that was clearly a marketing decision that earned her many millions more per year than playing for the USA.
I know very little about the rules in this. I had read that the skater renounced her US Citizenship to do that. It does sound more and more like sports team recruiting.