I once worked as a programmer (Mainframe, back in the late 80s/early 90s) so my experiences back then (last century!) probably don't relate to today's job market, but if programmers (in general) think they have an issue the unions can solve, go for it...
BUT, understand that you run the risk of your programmer union becoming like the teacher's union, where every teacher is considered equal, and any sort of merit pay is (literally) prohibited. Teacher's unions (the union most Americans interact with) treat each teacher are interchangeable/entirely equal cogs, with the only distinguishing thing about them to differentiate pay levels are "time on the job" and "level of education". Of course, tenure is a unique monkey wrench in the comparison - teachers unions enforce tenure, private unions don't.
Programmers, in my experience, believe themselves to be like snowflakes, each one unique and different, each one possessing a unique skill set that makes them worth just a bit more than the programmer next to them - a programmer's union would likely struggle to accommodate that belief.
Cory talks about "enshitification", unionizing "programmers" would be embracing "commoditization" of themselves - unions can be great when the worker skill set is easily defined and the workers can easily be replaced, it gives commoditized workers the ability to even the power dynamic between worker and company - programmers, on the other hand, neither regard themselves as "commodities" nor easily replaceable, and they will have to do so to be successful in a union environment I suspect.
My biggest issue with unions is that the workers form a union to address some (presumably) righteous mistreatment, but too soon the "union" thinks it is an equal business partner with the actual owners of the business and try to dictate business practices, etc. The cautionary tale for me is the Stella D'oro Bakery strike in NY years ago. See https://bronx-yes.com/en/etern... for a very worker-friendly version of the story, there's also a worker-friendly movie "No Contract, No Cookies" https://www.imdb.com/title/tt1...