That happens to me too, and I find it equally annoying, but I think it is a deliberate design choice. As I understand it they are trying to make it hard to accidentally turn off the alarm and go back to sleep, which would be a critical failure if you missed an interview or were late for work. Presumably irritation at the difficulty of switching it off is seen as the lesser of two evils
I find myself hitting stop instead of snooze, which may turn into a disaster some day. Simply touching your phone without care may stop the alarm.
iPhone alarm control became so wrong that I stopped using the screen and snooze only via top physical button. I’m not sure, but feels like it wasn’t like that before some idiot decided to change the way alarm works for sleepy subconsciously-trained users. Curious how many $M net cost was put into this “design”.
(Googled it: there was no stop button in ios 5, only slide-to-stop, which you cannot do accidentally)
When a timer finishes, you get a large button at the top for Stop, and a smaller one at the bottom for Repeat. When an alarm goes off, the Stop button is the small one at the bottom, and the larger top button says Snooze. Very often I find myself repeating a timer instead of stopping it.