It is because there are people just as stubborn as atheists when it comes to religious beliefs.
What forms of Egyptian are known from what times and places is not a matter of religious belief, but a matter of the historical record.
Everyone wants proof but are not willing to seek it themselves
I don't know what you're talking about. I can't speak for everyone in the world, but I went ahead and got a master's degree in linguistics, and my work for my thesis on the modern use of the Coptic language (the last form of the Egyptian language to be spoken in Egypt before the Arabization of the country) is what granted me that degree, after a year and a half of work in Coptic churches and monasteries with people who were actively working to revive the language, and hence spoke and understood it very, very well.
I think I did at least enough seeking to be able to answer the claims of an internet zealot.
We don't learn faith through proof
Again, claims about language that can be proven by looking at evidence present in the actual world are
not matters of faith, but of evidence. You can claim that the moon is made of cheese and you'll still be wrong even if you have a lot of faith that it is, in spite of the evidence. We have the testimony of the men who actually went to the moon, and the rock (not cheese) samples they brought back.
You believing things to be other than how they are does not change how they are. Only evidence can change that, and you don't have any.
It is not about the evidence that is known about what forms of Egyptian were spoken and written at which particular times and places. We are talking about the gold plates.
I guess you're right that it's not about evidence, since you don't have any golden plates to show any potential researchers, so
you don't have any evidence to begin with.
For people living in the actual world, there's plenty of evidence out there to show what forms of Egyptian were spoken where and when. While there is some debate to be had over the exact number of dialects of Coptic (mainly due to the difficulty in determining which ought to be classified as a 'dialect', and based on what degree of evidence; the standard answer I've seen in most academic references is six, though Funk 1988* suggests at least nine and possibly as many as fifteen), and some of the finer points of Egyptian phonology and other matters, in no academic source anywhere do you find mentioned 'Reformed Egyptian', as there is no evidence that any such thing ever existed anywhere, and it's not academia's role to bolster the faith claims of any religion or believer.
I found out for myself that the Book of Mormon is true.
You ought not trust yourself so easily, then, since the Book of Mormon is not true.
Joseph Smith could not have done so many miracles if he was not a prophet of God.
By "so many", do you mean zero? Because I think he proved that he could do zero.
*Post edited to include citation: Wolf-Peter Funk "Dialects Wanting Homes: A Numerical Approach to the Early Varieties of Coptic", in Jacek Fisiak (Ed.)
Historical Dialectology: Regional and Social. Mouton de Gruyter, 1988. 149-192.