Not 1000 protesters. 1000 DETAINED protesters. And during the same day the protests happened all over the country. I may have not been entirely clear in my comment, but you could've at least checked the Wikipedia.

Since the start of the war until 6 March [2022] nearly 13,000 have been detained.

And it's nearly impossible to calculate how many actially participated and escaped before getting detained. And that was before the mobilization, that was when only the professional military was involved. After the mobilization the protests reignited.

And what exactly do you mean by "Russians aren't passively resisting"?

In the months after the war started Russia arrested nearly 15,000 protestors. Many of them have been tortured by police after the arrests. We have video proof of that. Still after mobilization 2000 more were arrested. All of that after years of beating down on civil society. The problem with protests is that so far you only end up suffering badly for it. So the risk is just not worth it.

So what happened then was that over a million Russians left the country directly after the invasion started and more after conscription was announced. Pretty sure they did not feel like dieing for Putin.

You also have a massive chain smoking problem in Russia. Some of the targets do not seem to be very interesting to Ukraine, but very interesting for Russian anti war groups. One of them is the recent fire in the Wildberries warehouse near St Petersburg.

Hmmm let me see:

No protest: I get to have some extra time with family until I get drafted and some faceless soldiers die. (Assuming I have not been consumed by propoganda) Or protest: get fined/jailed and leave my family without any support

It's easy to say that they should just protest if you ignore protestors will also have to fight a genocidal regime.