Exactly right. Teaching any dogma, whether Jewish, Christian, Hindu, Wiccam, etc, as being "the truth" is harmful. Christians who claim to know "truth" are particularly amusing, since they have schismed into 190 or so denominations, each with their claim to "truth".
Surely, with 190 contrasting claims, they can't all be true. The pope does not speak for all Christians; Mormons do do speak for all Christians; Orthodox Patriarchs do not speak for all Christians; Ayatollahs do not speak for all Muslims, etc.
Doctrinal differences are manifest.
There is a common ground. An understanding that there is a natural world and it can be discovered by observation and evidence. This is totally different from faith notions of {poof} to "explain" any thing whatsoever.
We agree, except on one small point. While it's certainly true that "they can't all be true", there is objective truth. I certainly can't lay claim to it but just because they cannot all be true doesn't make them all equally untrue.