Why government mandated face masks for everyone during the Covid-19 pandemic?

Besides that politicians and societies in Western countries have become more and more extremely risk averse (precautionary principle) in recent decades there is probably another major reason for this unreasonable government mandate:

The majority of the population was supposed to protect the elderly (in the U.S. the 65 and older population make up about 15% of total population or every 7th individual) and other, particularly vulnerable individuals. 

And this despite the dubious protection afforded by all kinds of face masks that were being used by citizens often not wearing them properly.  E.g. some people were only wearing a net shaped like a mask. This is of course, the ultimate demonstration of futility of mass mask wearing that is not enforced! And how many people claimed medical exemptions to refuse wearing a mask? Apparently, the scientific evidence of wearing face masks to prevent contagion by SARS-Cov-2 is also not very convincing! Had government made more aggressive attempts to enforce mask wearing, the scam would have been revealed!

If there was not a government mandate, the elderly or vulnerable would be discriminated against or they would be stigmatized, if only them were wearing masks (even on a voluntary basis). To cover up any possible appearance of discrimination or stigmatization, we all were forced to wear masks!

If this assessment is correct, then politicians have failed to explain it to the public and to have a debate about it.

I am not sure any of this sufficiently justifies such social control measures as government universal face mask mandates! 

Voluntary mask wearing by free individuals plus providing the elderly and vulnerable with the best possible protective gear etc. would have been sufficient instead of these draconian government measures. Instead of focusing on the vulnerable, government wasted resources and efforts!

Lastly, but importantly, let's not forget that SARS-CoV-2 is a fairly harmless virus compared with plagues of the past. E.g. the number of death cases are highly inflated. More than 80% of all infected have no or only mild symptoms etc.