Just like I would not bother to buy and use a bike lock if people would not steal bikes in the first place. It's a bad analogy though, like all analogies are, since if I sell my bike I can't make it stop working for the buyer at a later time. But that's the big difference between digital and physical.
I have been working on and off on anti-piracy measures for my Lunar app (https://lunar.fyi/) and as much as I want this to not affect normal users, the app can still stop working after a decade or two if the Paddle licensing server doesn't respond as I expect it for example, and I'm no longer around to fix it. This could be regarded as DRM by some.
But I would have never wasted time with this if people would not crack my app in the first place AND demand customer support and flood my dashboard with errors unrelated to the normal functioning of the app.
If piracy isn't stealing, then protecting against it isn't limiting ownership.