It's stealing when copyright is infringed and when the stealing part is not acknowledged. Otherwise, can we called it "inspired by"?
There is something of a tradition in the design world to use theft-shaped words for things we collect for inspiration/ideas. A piece of advice I followed in the 80s and 90s when paper was still a thing was to have a "Swipe File," which was a collection of things you saw and liked, on paper.
In my own case as a designer of desktop apps, my Swipe File was not just digital screen shots of parts of apps that I admired, but I physically printed them out as well so I could spread them on a desk, floor, and walls when brainstorming.
That word "Swipe" also inspired the name of a design store catering to creative professionals in my home town, Toronto:
No, that's just copyright infringement. It's stealing when the stolen thing is no longer accessible to the previous owner.
Consensus differs on whether both, or just one, is morally objectionable. Conflating them is problematic.