These things don't really apply in Minecraft
Setting TNT takes no time at all, admins and anyone the admins want can have unlimited resources, and destruction is encouraged as long as you're not destroying something that actively belongs to someone
Yes, but this doesn't apply to any
normal players. Some people work hard for their resources.
If the owner of a house isn't online then what stops a player from thinking it's abandoned? "Oh look at this, a house with no players, lets blow it up for the lawls!".