Seriously though, to be fair, all religions proclaim that their faith is the one true faith and that all others are false, so it's unfair to attack Islam over that.
No, they don't, and no, it isn't.
Ironically, Islam isn't even the most extreme example.
Islam teaches that Islam is the true faith but that Judaism and Christianity are also true to an extend and Muslims as well as good Jews and good Christians will go to heaven.
Christianity teaches that only Christianity is the true faith and that one must accept Jesus as the saviour to go to heaven. (This does not mean that Christians are intolerant towards other religions.) Some sects of Christianity teach that Jews alone have a separate path to G-d.
Judaism teaches that Jews have to follow certain law to go to the next world while non-Jews do not. But Judaism does emphatically NOT proclaim that Judaism is the one true faith. In fact Judaism does not concern itself with the question of which religion non-Jews should follow as long as they don't pray to idols (i.e. physical objects).
Buddhism doesn't see itself as the one true faith.
Hinduism makes no such claim either.
Zoroastrianism (the religion of King Cyrus) is even mentioned in the Bible as another true religion.
Nor did most of the pre-Christian and pre-Islamic pagan religions make such claims. People usually accepted that every city had its own god.
The Israelites were one of these peoples and their god was the god worshipped by the people who lived in and around Jerusalem. What made the Israelites special was their belief that their god was also the creator of the world and that others, like Christians and Muslims later claimed that the god of Israel was indeed the god for everyone.
The Bible mentions a few of these other gods and even the Israelites until 2100 or so years ago still worshipped G-d and "Asherath". Prophets in the Bible decry such practices and archaeologists have found shrines to Asherath and other gods and goddesses in Israel.
In the Semitic pantheon Asherath was the wife of El, the creator god, and mother of most of the other gods. Marduk was the city god of Babylon and a son of El. Melqart ("King of the City") was the city god of Tyre. All of these gods were originally Sumerian.
"El" as a word means "supernatural" (or something like that) and it is hence where the Hebrew words for "G-d" derive (Eloah and the more polite Elohim) and the Arabic Al-Ilah (-> Allah) with "al" being the definite article ("the god"). (Note that vowels would not normally be written and hence all these words look pretty much the same.)
It is a typical assumption of people coming from a Christian background that religions are usually about proclaiming themselves the one true faith, whereas that is really only true for Christianity (and Islam to a lesser degree).
So, no, all religions do not proclaim that their faith is the one true faith.
And no, it is not unfair to attack Islam (or Christianity) over this particularly unpleasant attribute which Islam (and Christianity) has and other religions do not.