Because developers spend a lot of their day working with them.

And it can take a significant amount of time getting to grips with a new one you are unfamiliar with.

And you can often quite easily get yourself in quite a serious tangle with complex merges and operations done with VCSs leading to a lot of cursing and hatred for a particular tool.

A pair of shoes is just a pair of shoes, but I'd still quite like a pair I find comfortable, thanks.

Maybe, but it's not something worth making into a political issue into itself, when the GNU project has actual political issues in mind, as close as they get to when speaking of a Software stack, like making sure that the management of a certain project is as close to their ideology as possible, as a political organization which writes Software (which is what the FSF and the GNU project always were, and a pair of beneficial ones at that).

That's true, in a way, until someone tries to force CVS on you. Yes they are all sideline tools but once you get used to something, its the best thing in the world, until you get used to something else. Change is great, but not quite appreciated enough.

At work (where my script to convert all of our projects from CVS to Hg is complete for almost ¾ of a year now) I now resort to a hacky PowerShell script that allows me to work locally with Hg and then push selected revisions to CVS. Mostly because I fear that we won't ditch CVS for quite a while and when we do I'm probably the one to blame for lost developer productivity while we're coming to grips with a new tool.

So many wrongs in one comment. The fact you believe you'll be blamed for dev productivity loss is just not right. Blame? The fact you have to write scripts converting from one source control to another is not good, the fact you resort to hacky powershelling is scary. I wasn't even thinking the "are they still using cvs in 2014" even but I guess I should have. "blame" should exist in source control systems only.

Actually I was agreeing to your point that at the time when CVS is used version control is no longer "just a tool" but a PITA.

I'm the one who suggested conversion to a newer system, so when the other developers need to re-learn and lose a week of productivity that way it is my fault, to some extent.

My conversion script is essentially just automating creating cvs2hg config files for a number of CVS modules (and cleaning up before/after conversion) because our CVS repo is a few GiB in size, containing everything that ever existed (and plenty of things beside that) so a 1:1 conversion isn't that ideal, especially because it will lead to frequent (harmless) merges. But to developers with a CVS background merges are scary.

My cvshg PowerShell script is based around https://wiki.mozilla.org/Using_Mercurial_locally_with_CVS and http://pavelchikulaev.wordpress.com/2012/04/09/using-mercuri..., but tailored to how I use the tools. It allows me to commit happily locally and histedit later when I need commits I can actually share with others.

That's different then, I agree. I read your original comment as if you're tasked with something and then expect to be blamed for it.

Yeah, well, there are hammers of many brands, but few have claws on both ends, as the analogy for a certain controversial piece of technology went.

Some people will be fanboys of anything they spend a meaningful part of their day with, because (a) it makes them feel good about themselves, and (b) they don't know any better. They're still in the larval hacker stage where they still have binary opinions about everything, because they don't yet have the technical depth to have more nuanced and informed opinions about this stuff.

If they can convince themselves that the few things they know really well are the only things that are important to know, then maybe they don't feel bad about all of the things that they're just starting to realize that they don't know. That's my interpretation at least.

Well said! And that's exactly why i cheerlead for Mercurial. Because of all the rabid Git fanboys.