The 90% imposing unwanted hardship on the 10% is also easily described as tyranny, unless you're arguing that the interests of minorities don't matter?

I should clarify that I don't mean to say that this makes the protest valid, just that the argument that protest is only acceptable if an arbitrary number of people are involved is not all that good.

It critically depends on what you mean by "impose", I think it's a well known lesson by now (and actually very low-status and cliché to bring up) that masses can be convinced of anything, so the deciding factor is often who has the most efficient consent-manufacturing machines.

You could argue that consent, as traditionally understood, doesn't even meaningfully exist in a population above a certain threshold (say 10^6). Consent implies knowledge and understanding, in a population of 10^6 and up, in even a moderately complex environment, there is no way even 1/10 of the population understand more than their own very narrow slice of what their environment and society are doing.

You're aware of the imposition of the government upon the before-they-were-protesting protesters, right?

Congratulations, you have discovered democracy.