What's more important, since you mention the 'scientific consensus' and his claim that there isn't enough data is: What is the consensus on 5G (I suppose that means mmWave) and what are the studies it is based on? That would allow to make a factual comment on his claims about health hazards.
That’s true only if we indeed know nothing about 5G, and that’s demonstrably not the case. In fact, the pretend open-mindedness is tantamount to denialism, if we accept that findings on ≤4G translate to 5G, and there are good scientific reasons for thinking so, based on our established understanding of physics and biology. It’s possible that 5G changes the picture, and I am indeed open to the possibility. But at the same time intellectual honestly compels me to describe the chance of this happening as low, given what we generally know about the biological effects of non-ionising radiation.
Put differently: Given what we know, it’s honest to say that 5G might carry risks, but that there is currently no good reason to assume so. It is not honest to claim, as the article does, that “we have no reason to believe 5G is safe”.
This is a reasonable approach and it is a general approach. Now, about 5G, again the question is what we know or don't know about any risks.
If there are no or very few studies about the effect of mmWave then it is indeed reasonable to ask whether precautions should be taken.
You seem to suggest that there are indeed no such studies but that it can be assumed to be safe because emissions in a different part of the spectrum are safe.
Whatever the reality is, this is simply not a scientific approach and does suggest that you have no factual reason to believe that mmWaves are safe (or dangerous actually, you simply don't know).
I am not saying that he is right, but scientifically we cannot just counter his argument by "no, you're wrong".