In searching for the origin of this usage, I found this blog post[1] which attempts to explain arguments both for and against. But, to me, the arguments it lists under the heading "Why referring to people as resources is okay" are actually stronger arguments against. They're all about making certain management tasks easier by simplifying what's being managed. Unfortunately, this goes past simplification to homogenisation.
I've lost count of the times that I've seen management treat a big set of developers as equivalent resources, free to be reallocated to projects as needed. This approach never factors in how well certain people work together or the disruption caused by splitting up a well-functioning team.
It's not just that people aren't the same as objects; it's that people aren't even the same as each other.
[1] https://www.retaininternational.com/blog/why-are-people-call...
Talk about cringe.
(Colleagues in my world connote someone who might be considered as a research collaborator. Definitely NOT HR bureaucrats.)
Whowever decided HR being less offensive shouldn't make judgement calls like that at all.