It looks like the @matrix flagship server is currently under attack by far-right trolls.
All of the larger rooms are currently flooding with pornspam and slurs.
@matrix Was setting up a #Matrix Synapse server to play around with today of all days, only to find that joining a handful of rooms completely maxed out the CPU and RAM, mostly because it is downloading heaps of garbage from the matrix.org Synapse.
It looks like it was just the couple I tried to join. the matrix chat and the free software chat seem to be targeted right now.
This is the Vranas instance.