But his opposition outright lied and they knew it.
You’re just proving my point that it became more about sticking to your side and cheering for your team rather than relying on the medical evidence. This sort of stuff should not have been brought into the political sphere in the first place.
Many different measures have been implemented, you can't possibly pick one of them and say that particular one has had a definite impact on a certain thing.
At least where I live, the way that Covid deaths were recorded over the winter left plenty of leeway for those dying "with Covid" to have just died of the flu (to be specific, if a patient had symptoms or evidence of a viral respiratory disease being the cause of death, then all that was needed was a "clinical picture of Covid" to make it a Covid death).
It was massively irresponsible for a political leader to bring up anything that wasn’t actually shown to work at that point, and the ensuing shitstorm was entirely predictable.
The responsible, statesmanlike thing to do would have been to tell the public all the stuff that he was doing behind the scenes to find solutions, not throw out something specific but unproven.