Exodus 20:25 And if thou wilt make me an altar of stone, thou shalt not build it of hewn stone: for if thou lift up thy tool upon it, thou hast polluted it.
Based on this revelation, regardless of all other considerations, any altars that any humans have ever made that were built of any hewn stones were polluted altars. Any and all worship on such altars was defiled worship that was unacceptable to God.
We must not fail to notice that God never explains why that was true. As believers, we do not have any obligation to anyone to have to explain why all such altars were unacceptable to God and why all worship offered on them was ungodly, unacceptable worship.