The fact that two or more programming languages are particularly suited for a certain task has absolutely no bearing on the general usefulness of having conversations about what languages are good for. It has absolutely no relevance to state that; the discussion didn't become more or less valid by that assertion.

Discussions that are prolonged like that become long because people are not actually being _objective enough_.

If you had an objective discussion about Python and Ruby you would conclude that yes, both of these languages have very broad ecosystems and are particularly suited for scripting (and glue work). Python is better suited for scientific computing, etc.

Nothing about the scenario you speculate about invalidates good discussion about programming languages and I don't know what about the scenario makes you think it does.