There are people out there who believe this was all a hoax, that variation is all natural, etc. But we can see the ozone holes shrinking. We have seen that recovery slows when we emit new CFCs.
We stopped doing some genuinely useful and cost-effective things because it wasn't worth the cost of harming our health. We stopped doing it in every country on the planet, because it was causing a global problem.
Everybody signed on, there was a transition period, we initially made exceptions, but we gradually found replacements and banned more substances. In some cases the replacements still aren't as good as what we had, but our atmosphere is healing. Companies were making good money making CFCs, but now they're making good money making what replaced them.
And even for this seemingly uncontroversial success story, there are people out there who make up stories that contradict scientific consensus and direct observation.