Hamas seems to have become emboldened in recent days to seize control over various independent institutions. Last year it took over the doctors and teachers unions, expelling anyone who it felt would be a threat; earlier today Hamas raided a charity.
This afternoon Hamas seized documents and equipment belonging to the Gaza Dental Association, and it setting up a committee to take over the dentists' union, much to the consternation of Gaza dentists.
These sorts of stories were prevalent up until a couple of months ago and then they died down. It seems likely that in the wake of the one-sided UNHRC condemnation of Israel on Friday that Hamas has proof that its own human rights violations will be ignored by the world, and it is acting accordingly.