Pretty sure people offering differing opinions is not the same thing as invalidating the opinions of others.
Pointing out that something isn't practical, however nice/diversifying it would be, is not the same as invalidating or otherwise outright opposing it.
We have every right to criticize the creation we're a fan of; however, when you present that criticism on a public forum, other forum users have equal right to criticize that criticism or otherwise offer differing opinions.