Why would you want to Simulate your stimming online? That doesn't actually equate to stimming in real life, it's completely unrelated to the act of stimming.

Stimming is generally compulsory and often involuntary.

I have adhd stims and I usually don't notice I'm doing it until I've already been doing it for a while.

I know it's not strictly an involuntary action but They are not a choice one makes, its an impulse, unlike selecting a gif.

I've heard that things like drawing can be a stim but in those cases it's my understanding that what is being drawn is irrelevant.

The picture that results from it is not the stim, the action of drawing is.

It's not a deliberate form of communication. It's a repetitive habit whose effects and cause are internal.

Sure somebody might be able to understand how you're feeling as a result of it but it is not the purpose of the action, it's an unintentional byproduct.

The physical action of selecting a gif is no different than the physical action of doing anything else on your phone or computer. In either case you are pressing a screen or pressing a mouse.

Selecting a specific gif is also non-repetitive and non-continuous, it doesn't fit any form of stimming I've ever heard of.

If pressing a mouse or screen was how you stim (which is not what this person is claiming but is the only way this could even slightly make sense) then what you are pressing is irrelevant.

Stimming is not done in any case to deliberately show others how you are feeling.

People do sometimes deliberately start stimming in an attempt to intentionally use its emotion regulating effects. But that is irrelevant to this as this person is seemingly just "simulating" stims online which is nonsensical for the reasons I already said.

Even if they are autistic, which we have no way of knowing, this isn't an actual product of their stimming but rather a completely pointless decision they are making.