It's still a crap situation for Flurly and their customers, but if newsawp wasn't scammy or breaching credit card issuers' terms, then blame lies with whichever credit card company forced Stripe to take action, and if newsawp was behaving badly, then blame lies with Flurly for not doing a better job of vetting their merchants.
This why stripe is quick to ban merchants.
I would certainly not trust stripe to effectively "dispute the issue on behalf of their client", based on experiences some of my friends have had with stripe. More likely, stripe just folded instantly upon receiving some automated nastygram from the CC issuer.
Having worked at Stripe (though not in risk), I'd wager that Stripe did not "fold instantly" for a 425k fine. It's unfortunate, but the OP is the one who made a costly mistake when they grandfathered existing accounts into a setup they knew had liabilities.