Exactly. The main reason why governments are against Bitcoin mixers is because they can't benefit from them whatsoever. Since Bitcoin is a decentralized cryptocurrency, it gives the power to the people instead of middlemen or third-parties. Once coins are mixed, it's nearly impossible to revert back transactions. While governments are able to shut down centralized mixers, they'll be unable to confiscate mixed coins because of the decentralized nature of Bitcoin. Even worse, non-custodial mixers like TumbleBit and even Bitcoin Cash's CashShuffle, have no single point of failure making them difficult for governments to stop them. At some point, it's believed that mixers/tumblers would be considered illegal by worldwide governments as they present the excuse of people using these services for tax evasion.
As long as Bitcoin remains a fully transparent cryptocurrency, governments will be able to track & trace individuals for taxation purposes. And if it stays that way, expect Bitcoin to see the approval of worldwide governments within the future. Other cryptocurrencies which are private by default (like Monero and Grin) will be entirely banned by worldwide governments. The reason of this is obvious as governments don't want anyone to achieve financial freedom. They will always spread lies to the people about Bitcoin and other cryptocurrencies, related to criminals using these alternative payment systems for money laundering and tax evasion. With this false propaganda, it's no wonder why a large portion of people worldwide haven't adopted the pioneer cryptocurrency yet. Time will tell us what will be the fate of Bitcoin mixing services, as governments devise laws either in favor or against them. Just my thoughts