Yes, yes it is. The tyre is at a higher pressure than the atmosphere so any hole will allow the air to equalize but the difference is how that air comes out:

Stab the sidewall (big hole, rapidly) air rushes out with a big bang.

Snip the stem, smaller hole, air rushes out slower but still very quick. Likely flat in under a minute. Different structure/strength that sidewall which is why it doesn't pop/explode.

If you get a puncture, the reason it doesn't leak as fast as snipping the stem (nor pop) - usually the nail/screw is still in the tyre, keeping it plugged somewhat, the distortion of the tyre under weight means this hole can open and close as the car rolls letting out a little at a time.

Source: have had punctures that take hrs to run flat, have watched tyre techs clip stems on an old tyres, seen videos of tyres being stabbed.