Why would the ban of a centralized mixer by a single country (US) and only affecting the residents of that one specific country (US citizens), lead to a ban on Dash CoinJoin application ? In order to ban Dash CoinJoin application, you would need to worldwide ban Dash as a decentralized blockchain. A decentralized blockchain that offers optional privacy and where less then 5 % of its transactions involve CoinJoin transactions ?
If anything the Tornado Cash ban will lead users to privacy-oriented blockchains (Monero / ZCash / Firo) and in a much smaller degree to Dash.
I have difficulty picturing how the ban of Tornado Cash leads to a very specific worldwide Dash CoinJoin ban.
What could happen is that some local exchanges will exlude certain privacy-associated coins in their own local markets, but that is happening these days anyways.
And that mostly seem to impact the privacy-orientated coins, through delistings in certain select few markets (Japan - South Korea - UK - Australia).
Firstly you can't ban Dash in the same way torn was banned, it's not centralised enough for that. Secondly, now that certain regimes are waging war on financial privacy, we should double down on privacy since it clearly is an important aspect of Dash. Thank heavens Ryan (soft on privacy) Taylor is out of the picture now, the last thing we need now is him belly aching how we have to confirm to some amoral laws from a country run by privileged senile people with far too much power.