I'm having a hard time actually finding a source for this. Just a few poorly written articles that basically cite this video as a source. Something this potentially impactful seems like it would make the rounds more, so I'm very skeptical.

"sir, there's been a complication...it seems the mosquitoes with our gene are dying off in water ways and directly polluting the waters....humans may never be erect again."

As long as they can still get blood from other creatures too, I'm okay with it. If not, than that could have wild implications to the food chain assuming it leads to massive population degradation.

Why make them flaccid instead of just killing them?

Most species are invasive and not part of the natural ecosystem of most places anyway.