They claim this reduces the effectiveness of ASICSs as they can't do massive parallelization.
Bullshit.
ASIC-based miners are MASSIVELY parallel processing devices. Each chip in a miner can have over 256 cores and each miner can have many hundreds of chips with each core processing 1 hash for every 2 clock cycles. Well over 100 chips per hash board is very common. That is how they achieve from a few TH/s to over 100 TH/s throughput with a modest few hundred MHz clock speed.
Yeah there is a limit to how many chips can be effectively fed data per controller that that is not a serious limitation.