The people who fill the streets during protests aren't really "the left." Most of them are just members of the community, many of them haven't been politically engaged before, and they're protesting because they suddenly see that they're under threat.
Protests are not the result of some backroom scheming by professional Democrats who think brown-skinned people waving Mexican flags is good optics. You can try to organize smallish groups of protesters, but once it gets large enough you can't really command a large protest. He can be insufferable sometimes, but Will Stancil has a really good thread on this shit on BlueSky right now:
Don't peddle the "it'd be better if they weren't carrying Mexican flags" shit. That's giving in to GOP framing. You give them that and they'll find another angle and you'll give on that too, and you'll just keep giving because you think it's an argument. It's not an argument. It's a demonstration of common humanity and an assertion of rights and agency against the oppressive boot of the state. Anyone who wants to help, stop worrying about how the optics aren't as ideal for protesters as you imagine they could be and start thinking about how you can make the optics worse for Trump and his dipshit toadies.