There is currently a disastrous war taking place in one of the Arab world's most ancient and civilisations. There are of course other factors at work too, but that is the primary reason for the current flood of people (some are actually Christian) of a different culture into Europe. It's a state of affairs that is not going to stop, Schengen or no Schengen, EU or no EU, until either that conflict stops, or the refugee centres in the Middle East are improved to the extent that they become more worthwhile places to stay.
A London conference has just had its annual meeting to discuss and allocate funding for the latter. The U.K. actually already contributes well to this fund, but more need to be done.
If there were marched organised to call for an end to the bombing in Syria by government and Russian forces, and for other countries of the EU and beyond, properly to address the crisis, then they'd certainly get my support, rather than a protest against a dubious and rather nebulous 'threat' which inevitably will be seen by many as a witch hunt against people.
And yes, the counter demonstrators are not helping and should stay away