Reality check. Weight of these demonstrations is greatly exaggerated by biased media supporting this case, people tend to cherry pick their sources so it appears that it's supported by most of the polish people.
While the video editing makes these marches seem big, they aren't very widely supported and honestly from my experiences most of the people deem whoever participate in them hooligans or even criminals.
Don't fall to this illusion that nationalism is on the rise in Poland, it's still only a marginal phenomenon and there's still a lot of work to do, getting complacent and going with confirmation biases is the worst that can happen to these causes.