Nothing is entirely free from risks. That's part of why we do studies on things like this. But, for example, the second study on the page you linked concludes: "At the present state of knowledge there is no positive evidence that pulsed or continuous microwave exposure in the non-thermal range confers elevated risk to the health of the brain."
The mere presence of studies on a subject does not indicate positive evidence of material risk to health.
https://scholar.google.com/scholar?hl=en&q=microwave+exposur...
This is not to say that low power microwave exposure is worse than exposure to pollution, unhealthy food, risks of car accident.
But it would be incorrect to say that microwave transmissions are free from risks.