He wants to limit anything and everything that could be a check on his power.
State's rights sounds like a good slogan from the 1860s but in practice, it means the states have to stand alone.
Imagine California starts buying up all of the land in Nebraska. They could afford it.
Or Texas decides that Montana has too much land.
States can now dump unlimited funds into manipulating the elections of neighboring states.
States Rights means there will be no referee, no higher power to appeal to.
All of those coastal elites that Trump supporters hate can simply buy out the opposition.
Trump though, he has enough personal wealth to influence policy. The only thing the federal government can do is get in his way.

States Rights, JFC man think it through.
Those laws the federal government enforces don't oppress you, they protect you.
Without all of those federal agencies, one well placed bribe (no FBI to investigate) and toxic waste gets dropped right in the middle of Minnesota.
Without federal courts, a company incorporated in Texas gets to dump all kinds of fraking waste in Oklahoma.
What we're doing to China and most of the 3rd world by outsourcing our pollution our exploitative labor practices will move right back home.
Except it won't be poor Indian children working in sweatshops, it'll be Trumponians in Georgia.