How is it political? Deciding what would be the safest course of action to protect the health of others should be decided by those who know what they’re doing
Because there is much, much more to it than that. That isn't even a description of good public health policy, let alone of anything a government can do.
When governments make policy, they have to consider what the population will actually do. Otherwise it's pointless. Having laws people won't obey, and can't on a population level be made to, is actively harmful. This is why such an important part of pandemic management in the early days in particular related to behaviours and messaging.
In the UK at the moment, the political situation means we have a government that cannot, for example, implement more restrictions (or really enforce the ones we have) because of public attitudes and also the views of some of the legislature. That's politics. It means that even if 'the science' actually existed in some indisputable way, which it doesn't, it still couldn't be determinative because people's behaviour matters.
Put simply, it's shit public health policy to ignore what people actually think and are going to do. That's not to say you can't work to try and change those things (though our current government can't, because politics) but what you definitely cannot do is ignore them. Or you'll fail.