You are missing the primary thrust of the argument. They are saying: "This goes against known science -- proving otherwise would be a massive scientific discovery which would require reconceptualizing a century of work. This is highly unlikely".
Assuming the commenter is operating with robust scientific understanding [1], then there isn't any dogmatic belief here.
[1] I haven't researched this cellphone cancer thing personally so I can't strongly argue that point one way or another. However, my cursory understanding is that there isn't strong evidence for it.
Seems to be exactly what a lot of folks here are trying to do - „non-ionizing radiation cannot cause cancer, period.“
There are good scientific reasons to think cellphones don't cause cancer. However, if enough compelling evidence was found otherwise, then it would be important to update our understanding accordingly.
Science is not a static. Believing absolutely in a specific scientific result and refusing to accept that it may be wrong is as harmful to our advancement as those who refused to acknowledge that the earth isn't flat (they also used their limited understanding to justify their position).
To reuse your opening statement, you'd also win a Nobel Prize if you could conclusively prove that "your cell phone cannot cause cancer" and "any radio signal from a cell phone [doesn't]."