I heartily agree with this. I really dislike the tools that provide their functionality by mucking around with the shell environment in (essentially random after accounting for platform variations) ways ...

Tools like nvm, rvm, ros ... If I can use a solution for managing a development context that doesn't involve mucking around with the shell environment I much prefer it. Configuration via the sourcing of shell scripts is a very fragile interface, doesn't work when with good (ie non-bash) shell, and almost always eventually leads to bugs when some workflow triggers processes in a manner that fails to inherit the shell environment...

Fair enough.