What happened to these children was horrific, but framing it as a communism vs democracy/capitalism is pointless jingoism. The USA and other Western nations have their fair share of atrocities committed against children.
The thousands of children who were stolen from their families and abused/killed in Residential Schools were mistreated and abused in a society that viewed the practice as "democratic", "enlightened" even.
The idea of deformities making children "unfit" is just a form of eugenics, which was fully endorsed by the US prior to WWII.
To say nothing of Japanese internment camps, indiscriminate bombing of schools and homes in the Middle East, thousands of teens tried and imprisoned as adults in the failed war on drugs, children being stolen from their families and imprisoned on the Southern border, and countless other atrocities committed against children by our great nation. And right now the Western world is financing a military campaign in Gaza which has killed an unfathomable number of children.
Communism may be no better, but it's hard to argue it's worse.
That's a bold claim, do you have a source?
According to the linked article in the OP, 170k children went through this Romanian system.
According to numbers just from Canada's residential School system, over 150k children were stolen from their families and beaten, abused, and often killed in pseudo-prisons. (https://www.cbsnews.com/news/canada-residential-schools-unmarked-graves-indigenous-children-60-minutes-2022-02-06/)
Numbers for the US are hard to come by, but the US dept of the interior estimates that "tens of thousands" of indian children died in their residential School system. (https://www.bia.gov/sites/default/files/dup/inline-files/bsi_investigative_report_may_2022_508.pdf)
This isn't a competition to see who is worse. Virtually every country on earth has committed unspeakable atrocities, many of them are still doing so today. Acting like this was a product of communism doesn't add anything useful to the discussion and just carries water for the parties who continue to commit similar atrocities under Western Capitalism.