Because that’s how most people pronounce it, and it’s an uncommon word so most are guessing on the spelling anyway

People spell by sounding out words.

This post is literally the first time I've seen it.

Because when Zach Mighty Morphs into the Black Ranger... This is what it looks like.

https://youtu.be/NQawDn9g_9c

What did he say? Clearly he said MASTADON!!!!!!

English speakers, especially Americans, don't put much value in spelling, especially on the internet. Can't be arsed to Google it, or even look at the logo on the page they're on. Just wing it because it sounds right and they've never actually read it.

Then they do read it and continue to get it wrong anyway, because fuck you that's why, I guess?

Native English speaker here. Although I pronounce it Mast-a-don, I spell it Mastodon because that’s how it’s spelled and I know how to read and write. Also, I’ve never seen it spelled like that. English speaking or otherwise.

Because it's fuckign confusing that is why 🤣

It's to subconsciously avoid the closeness to Mast O'Don