The stated motivation (which you are free to believe or not) is that the site was used to organize a violent protest, and that they are not interested in the users who were merely exercising their right to free speech or assembly.

A bit late but...

There is nothing in the article saying that they are doing this on behalf of the president.

Nor that they are 'starting a register'. In fact it says 'any information prosecutors find unrelated to the rioting would be sealed and could not be shared by prosecutors with anyone else or any other government authority.'

And nor does it say that they are doing this to 'persons who hurt the feelings of the glorious leader', rather it says it is going after rioters 'left six police officers injured and caused tens of thousands of dollars in damage'.

So nothing you said could be have come from this article.

Not parent, but:

This is a federal search warrant pertaining to an ongoing investigation, not a facility that Trump organized to hunt nonbelievers, as much as you want that to be true so that your narrative can play itself out.

How are those things mutually exclusive?