Rarely do authors think about these kind of things.
The big ice spike on her head looks like roughly 1 kg of ice.
With the values for water content in the air from this table: at 30 °C (since the chapter is in summer) with roughly 30 g/m³, that would mean roughly 30 m³ at full water saturation would be needed to make this one ice shard.
Which is possible considering the class room has probably something like (6x10x3 = 180 m³) as volume. But the picture at end with the buckets full of ice are most likely dragon magic or they would have needed to cool down and dehumify enough air to probably change the local weather.
And what is in your eyes the difference to MD having the liability? Both are fans doing things for the community.
The person writing the statement in the OP knows it’s bad to be liable but expects the persons making MD to take that liability instead of themselves. Strange thought to me.
I’m only a reader myself, but I still thought everybody involved knew that the possibility of an DMCA takedown always existed and kept as much anonymity as possible to escape it.
In my opinion this could even strengthen everybody:
If MD doesn’t save anything identifying the uploaders, so no IPs and just the username and password, and the uploaders are smart enough to not have identifying things used in combination with MD, then it should make it harder for the publishers to duck everything up like now.