Are parents also supposed to be blamed if society as a whole would let thrive streets with permanent civil war, drug barrons, organized child prostitution networks and so on?

Of course parents must take care of their children. And of themselves. But they are only fragile humans and can bear only that much of a load in a day. Certainly there are people that drawn in negligent or even mistreating behaviors. That's not a valid reason to blame individual in general and abstract the societal constraints they all have to deal with. That's actually nothing special to parents.

Passing off responsibility to parents is already the status quo. Hardly political suicide.

Saying that companies should face some level of responsibility for their products is the dangerous move. That’s part of why the Internet has barely been regulated.

As soon as politicians are also included in these acts, then you could see a shift in their opinions.

Parents need to have personal responsibility, but corporations get to use section 230 to absolve themselves of any. Game seems rigged.