The same can be said about humans. An enormous amount of heat is no longer hitting the ground due to man-made structures in general, way more than dedicated solar farms. Very likely putting solar on roofs is more beneficial than letting it just heat up tiles/shingles, while the building shades the ground. You're basically arguing against building civilization. However, I think human's effects on ecosystems is worthy of investigating, but the "solar panels blocking ground heat" concern seems very tangential and likely insignificant compared to the concerns of human's overall impacts on micro/macro environments.

How significant a difference is it that previously it was hitting my roof?