I believe it's more of the threat.

Give us access, or we start paying attention to all that shady shit you do.

Less malicious than that, a Telco isn't going to spend legal time/money/firepower on someone else.

I thought about that. What shady stuff though? Can't just be polluting or bribing politicians, can it?

Usually debatable accounting practices, shafting customers on a breath-taking scale (see Wells Fargo), but also pollution. Bribes were legalized by the CU ruling that literally legalized bribery of politicians, so no worries there.

No one wants the popo snooping, because if they try hard enough, they will find things.

It's simpler than that. The government wants access to the records, and they give telcos two options: The easy way or the hard way.

Don't understand this, why would telcos fight against LE to provide access? Seems like the path of least resistance for them to go along with government requests, rather than something more nefarious.

Sibling post imagines an explicit threat to telcos, but there is very little threat on the other side, ie there is no incentive to stand up for their users privacy for these large bureaucratic / dysfunctional orgs, so why would they?

Huh? These requests are legal. They are complying with the law.