Do you find playing melee more difficult?

[Rayo]

You clearly haven't spent time using Keyboard control enough.
First of all, keyboard users can choose between Legacy and Standard control scheme, and camera control via mouse swipe is very swift and accurate, so even if you opted out and stick with backpedaling movement you can still perform quick backward movement if needed.
Second, tab target is a thing and people can still select enemy from enmity list.
Finally, even with standard WASD movement, keyboard users have access to at least 3x(7+) buttons at any given moment (1-5, q, r, e, f , etc. plus modifier such as shift, alt, ctrl)

While I'd rather not start having to get into why it doesn't matter how you press a button much less that I have used the keyboard control, I'm using observations from other people with the notion that the default settings of your control layout, whether you're on controller or keyboard can dictate your favored play style early on and likely future preferences.
For example, I was helping someone who has plenty of on both keyboard and controller but was new to FFXIV set up their controller, and I saw them play fine on keyboard. I asked why he wanted to play on controller and they said that he liked playing on controller, as he felt like he was moving more efficiently which would help his tanking, ergo you can conclude that one possible reason for people prefering a job can be affected by their interface choice
While I understand you can nearly make any keyboard layout effective, personal comfort and preference bias toward your controller or keyboard can naturally make you drawn toward certain play styles, unless you already have a clear idea of how you want to play a different job.
I myself played melee on keyboard fine through out the ARR main story , but I grew up on action games on console, so I have a preference to melee combat and controllers which I took up to immediately after digging up some older XBone controllers to hook up to my computer. now a days I can play any job with relative ease. I'm not saying its fact but that its a possibility