Piglin turns into a pig in the nether biome

I am using Minecraft 1.19.3 Pre3 release (the affects version doesn't allow me to type this in.)

I opened a nether portal in creative mode. Then I entered it and reached the nether biome. Then I spawned a few piglins using a piglin egg. Then i left. I entered the same portal a week later and found out the number of pigs is equal to the number of piglins I spawned (which disappeared). Some pigs died from the lava and gave me porkchop, but I was expecting piglins i spawned greeting me. I used the hard mode.

And one question, are piglins going to spawn in the peaceful mode.

Thanks.