The vibe down here is probably a bit more nuanced, and the calls to have SA back are a bit of a knee-jerk reaction to less than stellar results so its hard to be sure how it might go down.
There's a few things people could probably stand to calm down & reconsider, in my opinion...
Firstly, before the SA clubs joined URC Ireland were doing very well, and Scotland were definitely on the improve. Of the original nations in that comp Italy have improved - but mostly on the back of one club, so a tight integration similar to the Jaguares and Wales are dire. So correlation/causation etc its not necessarily true that presence of the SA clubs are making those nations better, nor is it true that the lack of them is why NZ has been struggling.
Secondly, people are really forgetting how bad SA's clubs were in Super Rugby in the last couple of years before the competition fell apart due to Covid. In 2019 only 4 teams won more than 8/16 games, and none of them were South African. In 2018 it was both better and somehow even worse, where 4/5 NZ teams won more than 10/16, and no other club did with Waratahs, Lions & Jaguares all managing 9/16. And in both years the worse of the SA teams had negative points differentials too.
Thirdly, because of the time difference and South Africa's challenges holding night games, the matches over there were at awful times and have almost no benefit for the broadcasters this side of the competition. To make it even worse, because of the expense of flying all that way the touring structure would see your home team disappear for 3-4 weeks so you would go a month with no match in your home stadium.