Untrue. The "guiding principal" for COVID regulations was that it is a very contagious and deadly disease. If it wasn't particularly either of those things (and just a mysterious "unknown"), the regulations would not have happened regardless of unknowns. With the widespread availability of vaccines it is (quickly becoming) no longer either particularly contagious or deadly, at least relative to other everyday threats we face.

We do know that the vaccines work, that is not an unknown. They work to protect both the vaccinated and the unvaccinated people around them. They absolutely work to protect against the variants as well (with some bit of decreased effectiveness for the still very uncommon SA variant). There is no conceivable mutation that will completely circumvent efficacy of the vaccines and make it as deadly as the virus was previously (i.e. before the vaccination campaign).

Continued forced isolation and de-socialization as people have experienced under restrictions and lockdowns (though useful for pandemic damage control) are absolutely high risk as well- from a social perspective, from a public health perspective, from a psychological perspective, from an economic perspective, etc. They are important short-term tools, but should also be employed with "extreme caution".

With all of that said the reopening for giant sporting events probably could have been more titrated. I guess the line of thinking was other states have been doing it was out significant issue.