My former text was too long.
Consider the following facts:
- "Correlation does not imply causation" (https://en.wikipedia.org/wiki/Correlation_does_not_imply_causation)
- Reliability: The internal reliability of the study seems pretty bad (i.e. no randomization at all and there are other likely explanations for this relationship), the external reliability is unclear (is this related to YouTube users only?).
- Can they replicate it?
- Do they have a comparison group? (i.e. did they check if "YouTube left-wing people" become more left? Or did they compare against non-YouTube right-wing people?)
- Validity: Did they measure "YouTube makes you more radical" or just "Video platforms makes you more radical" or simply "the internet makes you more radical"?
So many unclear questions. So no, I don't have too much respect for studies only because they throw data together. If people would be more careful with what they claim then this world would be a better place.