Once upon a time there was only one Buddhist - the Buddha himself. Now there are lots. How did this happen if it wasn't by 'proselytising' their truth because they felt that was the loving thing to do. The idea that a group of people has amazing news about how the universe works but refuse to make any effort to share it makes no sense to me.
Yes, I get that at times 'Christianity' and 'Islam' have been imposed by force of arms. But that doesn't prove that the religions aren't true, merely that some people didn't fully understand what the religions really pointed to - though there's a case for arguing that Islam is committed to spread by force, as Ayatollah Khomeni wrote:
'Islam’s jihad is a struggle against idolatry, sexual deviation, plunder, repression, and cruelty. The war waged by [non-Islamic] conquerors, however, aims at promoting lust and animal pleasures. They care not if whole countries are wiped out and many families left homeless. But those who study jihad will understand why Islam wants to conquer the whole world. All the countries conquered by Islam or to be conquered in the future will be marked for everlasting salvation. For they shall live under [God’s law].... Those who know nothing of Islam pretend that Islam counsels against war. Those [who say this] are witless.'
Barry M. Rubin and Judith Colp Rubin, eds. Anti-American terrorism and the Middle East: A documentary reader. (Oxford: OUP, 2004) 29.