Interesting. I said this at my work recently and I got a condescending explanation about how production things are production, we don't touch them. If we need stuff for development, those are dev things.
I now think that whether this is or isn't a good idea depends on specifics. Most often than not, I think it makes sense.
It's also possible to test against live production instances and data itself (mostly useful for performance optimization work and testing), although that's more of an ad-hoc process and some kinds of tests are not possible because the actual data there is arbitrary. Also, those tests, if not used for development, might be better expressed as self-checks done on system start and monitoring systems.
The further you steer dev environments from production, the more you'll have these kinds of issues.
Would you mind expanding on their explanation? The way you described doesn't sound like an argument at all.