This is just cherry picking to paint a skewed picture. These votes were there to help make certain decisions - not to be leading. Regardless, the majority of the vote outcomes were used to determine further changes. Some weren't. 12 out of 18 vote outcomes were put in the final patch. Would have been 13/18 if Relic hadn't vetoed the T-34 Ram to vet 1 change.
The M20 vote was taken into consideration: the build time reduction was reduced from -20s initially, to a middle ground of -10s in the final patch, with room to further reduce (remove) it in a follow up patch.
On Assault Grenadiers I agree that the nerf was overkill, although the current option is similar or even better than the one that was voted on (sprint behind vet 1) by you amongst others. I think a simple cost increase (and cost reduction at vet 1) would've been sufficient. It was a last minute change without any testing and imo it was a mistake to rush this in.
I was a bit harsh I'll admit, but it was frustrating, because the m20 shouldn't have been buffed in the first place, and now we're seeing the consequences of that in the 1v1 scene.
As for assault grens, out of the three listed it was hit the least by the nerfs, and it's still, semi-viable, though only for specific maps where you have advantage (IE faymon).