Keep in mind that whenever a new application appears, detailed technical analysis and simulations have to be done with regards to the other applications in co-channel and adjacent channel/bands, both with regards to direct interference, aggregated interference taking into account the projected density of the new spectrum use, clutter/terrain, propagation models, geometries of antennas, filter characteristics, etc. And even then, administrations do their best to find the right balance and enable as many applications as possible (including unlicensed and SRD), but those are tradeoffs and sometimes administration take risks to foster innovation (and sometimes it proves it was too permissive for the new user, such as what is happening now with regards to wifi vs weather radars).
(N.B. I am not in the US, but I guess FCC works similarly to EU administrations - which I know very well).
Following the rules (DFS) is fair ask to be able to access these additional 5 GHz channels.