Small-scale spoofing, a/k/a pseudonymous / anonymous whistleblowing or commentary, can be useful, and has a very well-established tradition.

The goal of, effectively, all robocalls is fraud or value-extraction from the system. It works only because of the scale possible.

Small-scale operators (unless hugely and widely distributed) don't exhibit these characteristics. A fundamental problem of robocalls is the scale of operation itself.

Scale matters.

Countermeasures which disrupt at-scale operation whilst protecting small-scale activities are net beneficial.