I don’t support the idea that laws should be introduced without reasoning behind them. There’s absolutely no evidence whatsoever they help to reduce transmission in any way, it’s simply a guess by the government on how to make people feel “safe” and to pander to the hardcore lockdown enthusiasts screaming for tougher restrictions.
Well so far as I know there is evidence, although weak.
Since you're so keen on evidence, can you give me some that the government has actually introduced them for the reason you claim?
If there was a measurable decrease in countries who mandated masks then this would suggest they are effective, but given this is not the case it suggests otherwise.
It really doesn't because other things are changing.
Let's take an example - can you find a graph showing that public transport and road usage has remained constant since face coverings were mandated in the UK? If (as I think is the case) both have increased, that shows that face coverings aren't the only thing that have changed interactions between people.
You have to compare to what would have happened without face coverings and we don't (can't) know that.