[Some of this may be slightly off, you may have better translations than a google translated web article or a wiki article, but even so the claim that Allah is Baal is easy to doubt.]
I have come across many people who dismiss the idea that Allah is just a term for god, the most recent example was from a Christian youtube commenter, he claims that Allah was 'Baal-lah', or Baal, an ancient god noted in the bible. The problem is that you don't confirm this as factually the case with an argument stating what you reckon, and besides the origin of the term Allah seems to come directly from the Aramaic term for god, 'Alaha', meaning that it was the probable term used at the time of Jesus, for god. It takes almost no research to find this information, and almost none to discover that Maltese Catholics still used the Arabic term for god in their worship, not that the root of the Arabic gods is so simple as getting the concept only from the Abrahamic traditions, although there is not direct link to Baal and other gods noted in the Torah(Old Testament). Interestingly, the term 'Al-ilah' is the direct ancestral term for 'Allah', and acts as the middle phase from the Aramaic term 'Alaha', and it simply means 'the god', as opposed to merrily one of many gods, whereas, 'Baal' is a title that refers to a deity within the Levant, the term 'Ba'al' simple means 'Lord', representing fertility and storms, and as a Phoenician deity, it is understandable that Israeli cultural supremacists, the ancient Hebrews, would write a biased history founded on their religious dogmas.
Before anyone presumes that Islam came from another religious of legend, you really should study the pre-Islamic history of the region, not least that of Christians of Arabia, not least king Abraha, who controlled large areas of Arabia in the sixth century, such Characters cemented Judeo-Christian myths in the region, often alongside the practices of other cultures, such as Persian traditions. Most of this is a click away on any number of educational sites, the average person has a vast and powerful resource at their fingertips, yet fail to search beyond what they reckon the case to be, and typically from a position of ignorance. With the history of the Arabic faiths, we find many similarities to their neighbouring cultures, and some of those seeped through into Islamic culture, mostly the Judeo-Christian myths, with cultural inflexions of the Arabian People. The later followers of Muhammad seem to have collated the Qur'an and Hadiths with the bias of Judeo-Christian ideals, and possibly during the time after Muhammad's death, they may have engineered a belief that fitted their understanding of the restored one true religion, as they may have seen it. In the time shortly after the time of Muhammad, it was seen that the teachings of the prophet we largely being ignored or forgotten, what was written was in some cases contradictory, new translations, often into languages that could offer ever greater interpretations, the religious authorities, as a result, standardised the Qur'an, taking care to destroy rival Qur'ans. If this is historically correct, then how do we know we have the true Qur'an before us, the best you can do is lie, as most Muslims do, and claim that it was written perfectly, and the Caliphate of the time, only restored the true Qur'an to its rightful place, and destroyed translated works, since translation changes god's word it must be forbidden, or at least not truly the Qur'an, and not truly God's word.
Muslim authorities have disagreed over the details ever since the first page was written, or so it seems, so although Muhammad died in 632CE, most Muslims agree that Uthman compiled the manuscript of the Qur'an, during the third caliphate, over a decade later, meaning the word of god was not perfectly preserved in it's perfect written form with no room for error, after the death of Muhammad. For continued confusion, look at the Hadiths, a selection of actions and sayings of Muhammad, collected in an even more sketchy fashion, and out of many tens of thousands of sayings and stories attributed to Muhammad a very few were incorporated into the Hadiths, over two centuries later, and experts agree that many sayings are rewrites of pre-existing idea within the middle-east, including some the lord's prayer. We cannot be sure that the Qur'an is truly what Muhammad believed, and the Hadiths is plagued by things that you cannot know are historically correct, and the radical claims make the books of Islam seem like poorly thought out fiction.
Islam is false, you do not prove this by assertions, you confirm it by refuting the unrealistic views, regardless of which older beliefs it borrows from because those older faiths are false too. Feel free to disagree.