Complete and UTTER NONSENSE
"Yes, it's all true. Your IP address can change. "
Wrong. It may be true for SOME people but for others the IP address will remain constant for months or even years.
Besides, what has the ABILITY to change got to do with the price of eggs? I can change my home address, but while I'm living in it my home address is still very definitely personal information. Even if I share it with somebody else. And it remains personal information about ME, even when I stop living there. Its part of my personal information history.
I could change my name (and if I was female, I probably would at least once) -- but any name I use or have ever used is part of my personal information.
Equally, anything I've ever done in my life is personal information -- and even if I stop doing it, what I've done is still personal information.
So stop talking nonsense and admit that IP adresses are without any shadow of doubt personal information.