It's kinda true if you're thinking purely about submitting requests through `<form>` elements - but even then you can bend browsers to support other verbs.
There are multiple RFCs with lists of HTTP verbs and axios only supports the more limited set, which for my particular legacy project meant I couldn't use any of the creative ones.
That really just sounds like an axios issue - I've built in support for custom verbs with nothing but plain-old ES5 javascript. The verb is nothing more than a string component of the HTTP request and it's pretty trivial to modify it to your liking (even outside of standard verbs!).