Why such obsession and trust in measuring everything?

I'd like to ask in order to challenge, understand and find arguements in my further discussions about huge (and in my opinion blind) pursuit towards measuring everything (yet wrong things in a broken way).

The context is that managers wants to have clear metrics in order to evaluate teams and individuals, and I totally understand the need and sensibility of this when doing for teams and departments.

The issue starts when metric obsessions are adopted for individuals. (Note that it was proven long time ago that measuring lines of codes or bugs per line is very bad, thus I'll skip this from this post).

In most common scenarios, individuals works in the context of a team (rarely alone). When a team is being given a task (e.g. improve package dispatching or reduce help support calls) it's impossible to determine how much each individual contributed to that initiative/metric.

On the other hand, if an individual is being given a goal "improve best practices in the team" or "help junior developers grow" this things are highly opinionated (the result of that is an opinion of who evaluates that initiative, thus highly subjective).

I had 2hrs discussion with my manager, when he/she asked me to propose my very own Goals and Metrics. When I said I can find goals, but can't find metrics (because of reasons stated above) and I asked him to propose some objective metrics he/she was struggling to do so, proposed only subjective, opinion-based ones, and of course, didn't admit the I was right, and that it's hard to find so.

Thoughts?