Please be specific - which intelligent people? Who disagrees with them?
"Electromagnetic pollution one of the main source of its decline"
What are the other sources? How do they compare to electromagnetic pollution in terms of impact?
[1]: https://phys.org/news/2020-09-mobile-insects-german.html
[2]: https://sci-hub.st/10.1016/j.pathophys.2009.01.007
[3]: https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.10...
Second article lists it as a "potential cause"
Third article defines it as a "possible cause"
I have a hard time seeing how "the science is unequivocal in that the impact is significant, not negligible.", from the articles presented.
What I read is that EMR is a possible cause among many, like known contributors such as loss of habitat and pesticide use, but there further research is needed.
This is not the same as saying it's not possible that the effect is true - there just isn't enough evidence to support a definitive conclusion on the impact at this point.
I'm not an environmental scientist, so I don't have the required knowledge on the current state of research in the area. There might be newer research that is solid enough to warrant making a definitive statement, but what I read in these articles definitely does not.
Although research like this is definitely very important. I would just be wary of drawing conclusions without listening to the opinions of people with more knowledge in the field than you or I.