Why is Alola Exeggutor a Dragon type?

It is because it is most likely based on the Dragon Palm Tree/Dragon Trees and that it possibly has Dragon in its name in a different language. I do not know what language that is, just know I saw someone mention it. But the main reason is because it is based on a Dragon Palm in most cases.
 
It has a long neck and a tail so it very vaguely looks like a dragon
 
Icy has explained it - Alolan Exeggutor is based on a Dragon Palm, and I guess Game Freak wanted to make an interesting take on it by making it a Dragon-type.
 
I will say, it's been funny seeing all of the memes on Facebook about Alolan Exeggutor being a Dragon type, yet the more logical appearance of Charizard (regular) is not a Dragon at all. XD
 
I know some people found the Dragon typing on Mega Ampharos very random at first, but if you're someone who knows your Pokemon name origins you'll likely know Ampharos' Japanese name means "electric dragon" so it actually makes sense in that manner.

I love how Game Freak go more in-depth when it comes to a Pokemon's origin.
 
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