Absolutely not. There are multiple reasons.
First, al-Jazeera was originally run by Arab nationalists but these people were replaced by Islamists about four or so years ago. It is thus a radical media outlet run by people who are anti-American, anti-Christian, antisemitic, and anti-Western. In other words, it is an instrument of extremist revolutionary movements. On a number of occasions it has lent itself to promote and be used by violent terrorist groups.
Second, while al-Jazeera is more open to dissenting views than previous state-controlled media this is misleading. It is more open in English than in Arabic but former staffers in the English-language section have spoken about how it is not a free agent but the news is slanted to please the Qatari government which owns it. (They wanted to moderate the tone but the management objected because the owners wouldn't like it.) So al-Jazeera is also an instrument of concealed propaganda.
But there's more! Qatar, except for the (possibly soon to be overthrown) Syrian regime, is the most pro-Iran Arab government. It brokered the Fatah-Hamas deal which soon led to the Hamas coup. Far from objecting to the bloody Hamas takeover of the Gaza Strip, Qatar supported Hamas to this day. It is also the leading supplier of arms to the Muslim Brotherhood in Syria. On every issue, Qatar has taken a more radical, anti-American positions than all other Arab countries except Syria. It also was a key financier of the overthrow of the Libyan regime. This was in line with U.S. policy but there are deep suspicions that it has its own candidates for Libyan leadership in future more radical than the current regime.
So Gore had every reason to know what he was doing.
2.) Do you think al-Jazeera is using Gore to gain legitimacy?
Remember that as a station Gore's property is worthless. No one watches it. The thing is being bought only to gain its access into American homes.
Finally, a speculative point. Who is going to watch al-Jazeera most? Presumably the kind of individual who will find its ideology and indoctrination to be congenial. It will make them hate America, the West, real democracy, and Israel even more. As they watch al-Jazeera's exaggerations and fabrications of anti-Muslim violence as well as its glorification of terrorism, might they be more inclined to engage in violence?
Incidentally, there are even Arab television options to al-Jazeera. If he had sold to al-Arabiya for example it would have been much more acceptable since it is more moderate.
By the way, remember that al-Jazeera is controlled by an oil-producing state whose goals include maintaining the highest possible use of petroleum, a goal that is contrary to Gore's obsession with what he says is the threat of man-made global warming to destroy the planet in the near future.
And the basic answer is no: he is giving credibility to a pro-terrorist, radical, anti-American enterprise which is only apparently more moderate in its English to better achieve its goals.
PS, for those interested (as some readers have requested) a bit more in-depth information.
Finally, if you've read to the end you deserve a reward so here it is. Although I have to be vague here, responsible and reliable people in Israel have discovered in the past that al-Jazeera tried to send into Israel as staffers people with active connections to terrorist organizations. I have heard the names and details on this point and am satisfied that it is true. There's more of this kind of thing than I've explained here.
Barry Rubin is director of the Global Research in International Affairs (GLORIA) Center and editor of the Middle East Review of International Affairs (MERIA) Journal. His latest book, Israel: An Introduction, has just been published by Yale University Press. Other recent books include The Israel-Arab Reader (seventh edition), The Long War for Freedom: The Arab Struggle for Democracy in the Middle East (Wiley), and The Truth About Syria (Palgrave-Macmillan). The website of the GLORIA Center and of his blog, Rubin Reports. His original articles are published at PJMedia.