It isn't:
"[..] people confuse negative reinforcement with punishment, but these are two different concepts"[0]
[0] https://www.webmd.com/parenting/what-to-know-about-negative-...
Children are not small adults, but they are surprisingly capable of understanding incentives.
"If you behave well you can have ice cream. If you behave badly, you don't get ice cream. It's your choice."
It's awful to teach children that behaviour doesn't matter. Actions do have consequences.
You can't just redefine it as "not punishment" because you want to use that method in child rearing.
"Actions have consequences" as a statement isn't really up for much debate, it's more of a observation on how the universe works. If we fall far enough, we hurt outselves.
Gravity isn't punishing us when we fall, even if it may feel like that at times - the scars on my right arm from a cycling accident last year are still visible.
I'm not saying you're a bad parent for punishing your child, I'm saying you could be a better parent if you stopped leaning on punishment as a parenting tool.
Also, stop telling your child you aren't punishing them because they will ALWAYS remember that bullshit. At least own up to the fact that you are punishing them and tell them why.
It is amazing the mental hoops people can jump through.
Our eldest had his computer briefly confiscated not that long ago. He was, of course, cross with me when it happened.
The day afterwards he came to me and thanked me for taking it away(!)
Him: "I was spending way too much time playing games, I see that now" Me: "You're welcome to have it back" Him: "No, I'm not sure I want it in my room. It's too much of a distraction"
There are plenty who believe that withdrawing privileges is an entirely normal and appropriate response when children misbehave.
This isn't punishment, although some children consider it to be.