Actually a WordPress developer does both backend and frontend. They should know JS, PHP, react (for Gutenberg) and still some others think they are not programmers.
Next time someone tries to bully me about being a WordPress developer, I will not be quite. Even my friends.

Well there's wordpress developers that creates plugins and themes and there the install plugin call it a day type of people,

The perception and hate for the platform could be misguided since the title of wordpress developer often times are undistinguishable from people that are not technically knowledgeable

People can add and edit some pages on the wordpress backend but that does not mean they are developers, it just means that the platform can be used by non technical people.

@DevRage i had to mention that, by "my friends" I mean developer friends :)

If you are douing custom php in wordpress, you are doing wordpress wrong. /my 2c