Because honestly, about 90% of the things people call plotholes here aren't actually plotholes. I've heard someone call Obito's clothing changes from meeting Team Minato a "plothole".
Plot holes are things related to the actual PLOT.
Ex. Itachi, not being an established sensor type, was able to find Naruto in the woods the day he gave Naruto Kotoamatsukami.
THAT is a plot hole, as it was never explained HOW he found Naruto, and it also related to the plot. What I'm saying is, some people don't actually know what plot holes are, and Naruto contains fewer plot holes than most here think.
I think another thread really sparked this rant lol.
But yes, DBZ is known for plot holes. A lot of mangas have plot holes.