While ignorance of the law cannot be used as a defense for breaking it, an organization such as FTX comprises a complex interaction of financial, technological and legal issues. You can easily imagine naive hands breaking multiple laws in their ignorance.
It is also possible that they did things knowingly illegal only after their lack of experience had put them into a situation where they were trying to stabilize a teetering house of cards.
Some things are hard, very hard. In some domains, being clever without being an expert doesn't work.
It is also worth mentioning that the media sources that said how great things were going are also the same ones that are telling us how badly it ended up. I say 'possible' and 'imagine' above because we can't really get a good picture of what happened from reading a few articles. There will be a few good well researched summaries in a few years time. Hardly anyone will be interested by then; besides, the truth will be boringly complicated and nuanced.