I don't see anyone on this thread really being "wrong." You're just kind of talking past each other.
As far as I can tell, there was legitimate reason to be concerned that the Vaccines and some treatments would be less effective against Omicron than against the Wuhan-wild and Delta variants. That concern still exists, though is fading based on the very early reports.
Still, the problem is that we have been so used to government regulation in this field that we have everything backwards, as opposed to pre-COVID mentality. Travel restrictions and mandates used to be mechanisms of last resort. As far as I'm concerned, the burden of proof, before you hurt people's livelihoods, is on establishing that there really is a danger.
To punish south (small "s" ) Africa Because the South (big "S" ) African medical community was quick on the draw to take this news to the world was classic panicky shoot the messenger; cowardly, almost.
What Israel did, in banning travel at the first hint of any possible risk was insane. If they thought that was going to stop Omicron from getting into the country, They were being hopelessly naïve. Most of the people in Israel are triple-vaxxed and there have been no reports than Omicron is worse than other COVID variants (the reports that do exist indicate it's probably more benign). So, they dealt a blow to their economy and imposed major inconveniences on many people to look busy, on a standard of action that would've been unthinkable two years ago. Biden's tightening of travel requirements is more of the same.