Any religion immediately claims that all other religions are false, which is directly harmful to adherents of those other religions.

?? Since When? Some may - and some denominations/sects claim the same - even in relation to other branches of their own faith. Others do not and never have.

And directly harmful????? That makes about as much sense as saying that calling someone a name is directly harmful. Hurtful purhaps, harmful only if allowed to be.

And even among the various Christian denominations the "duty" to convert is of greater or lesser or no importance depending on whom you talk with.