I've been seeing this totally organic discourse popping up in 
comments. They found a new silver bullet that allows them to ignore anything being said
Democrats clutching pearls instead of fighting fascism is going to get fascism faster, and it will be all the fault of leftists somehow
It is grammatically valid.
"The <adjective> Party" means the party that values the principles of <adjective>.
"The <noun> Party" is the party comprised of <nouns>. The "Carpenter Party" means the party comprised of carpenters. The "Plumber party" means the party comprised of plumbers.
"The Democratic Party" is the party that values the principals of Democracy.
"The Democrat Party" is the party comprised of Democrats.
Denouncing the Democratic Party means denouncing the principals of Democracy. Denouncing the Democrat party means denouncing the people who call themselves Democrats.
I thought this post was about reddit getting mad that the word "Democrat" was used at all to describe a member of the Democratic Party, and I was making the point that of course they do, no one's gonna call a member of the Democratic Party a "Democratic." But people explained what this post was about below.