The Argument for Islam is very Simple:

[Crunchy]

In that case, it would be best to treat History like Science and respect the consensus of historians while setting aside any personal dislike of religion. So in this case, that consensus is that Muhammad was a real person who founded a religion just like Joseph Smith or L Ron Hubbard did.

No.  I want to see the evidence.  You see, when I ask for evidence on "jesus" all I ever seem to get is bible bullshit.  Not surprisingly, when I ask about the evidence for mohammed all I ever seem to get is the fucking koran.  Again.  I want to see the evidence not listen to some alleged bullshit consensus. 

If scientists reach a consensus on no evidence they should quit.

One of many many examples: https://www.rnw.org/archive/evidence-say...ad-existed

Global warming deniers do exactly what you are doing. They ignore the consensus of professional researchers and have formed an industry of denial.
I've already told you that there is non islamic contemporaneous evidence for the existence of Muhammad. If you care about the truth you will set your own desires aside and look into this like a robot would. 

If, however, you really hate religion and want to stick it to believers then by all means continue to deny the existence of their founder. Just be aware that you are strengthening their position when you oppose historical consensus. They can easily point out the evidence and rightfully accuse you of bias since you ignore the evidence that doesn't fit your desires. (which is what they do also)

https://www.opendemocracy.net/faith-euro...d_3866.jsp