No one ever said, nor has Jagex claimed that there bot detection system is flawless. Think of it like airport security. Will the metal detectors pick up EVERY harmful object? No.. Will it SOMETIMES wrongfully detect harmless objects? Yes...
Jagex has to balance creating and maintaining a bot detection system given there limited resources, and clearly they are ok with 99.9% of people they ban for botting actually being bots at the expense of the 0.1% that are wrongfully banned (this is hyperbole).
From my experience, With a large sample size of playtime over a long period of time it is extremely easy to spot a bot. Bots tend to click within two random variables. Even random variables become obvious when the standard deviation does not change over multiple hours. Humans cannot maintain clicks within strict boundaries for long periods of time, no matter what you say.
For example, randomizing a click to vary between 1-5 seconds may seem random on face value, however, even these random clicks will average to 2.5 seconds quickly.
The simple answer, Jagex does not ban based on whether you visually look like a bot. They ban based on multiple criteria after analyzing player data. Of course, “looking” like a bot may/will lead to influx of player reports, which is baaaad.
It's also worth noting, a lot of skills players may look like bots, especially while training AFK skills. When I see a fisher that has been standing still 60 seconds after the fishing spot moves, I don't accuse of botting, because let's be honest, most OSRS players multitask, alt-tab, or have a second screen.
Cheers,
SOCALEMT