I don't know why anyone wouldn't assume that any VPN service is run by an intelligence service, potentially one hostile to you, or organized crime.
Consider-- people bring their traffic to you to monitor, and particularly people who are trying to conceal their identity or activities. They pay you for this, which means that if you get collateral benefit you can run at a small loss and undercut any legitimate players (if there are any!) or run levels of advertising that a legitimate business couldn't sustain. -- while its simultaneously one of the most cost effective surveillance plays you could imagine, since it's still primarily funded by the victims.
VPN services also have good deniability for their surveillance. Although (maybe!) your ISP can't surveil the VPNed traffic the VPN provider's ISP can as well as your counterparties ISP (and any other parties brought into the mix by things like third party content). And like any other electronic surveillance, parallel construction can be highly effective.
They can also be stood up by anyone, you can run any number of services. They don't require extremely extensive physical infrastructure, investment, large numbers of employees like running an ISP. You can even target particular actors or populations by using targeted advertising, though it's still most effective as a data hoovering operation.
Particularly for the intelligence actors they also have the benefit that issues like getting harassed by the state are among the complications of this business, but that is potentially less of an issue if you are the state.
And if there were an actually honest provider, they'd be a prime target for infiltration... all that interesting traffic in one place.