Clearly not, as many people disagree with you.
> they don't want the workers to know there are viable alternatives to working at $JOB, because it makes their (mgmt) life harder.
Every decent tech professional is fully aware that they have the option of leaving. Management don't want you encouraging people to leave, sure.
Where I work, we have a Slack channel dedicated to this kind of talk, and most managers are in it. It’s been just fine.
The 5 day work week has a historical basis and it has nothing to do with 'keeping you from a side job', nor do most managers concern themselves with these kinds of issues whatsoever - other than leaking company IP or working for a competitor etc. - but those are knowledge worker issues that having nothing to do with most jobs.
The conspiracy theory doesn't even make sense considering the vast majority of jobs are things like: 'truck driver' 'school teacher' 'nurse' 'construction worker' 'accountant' 'retail banker' etc..