I always wonder "when did that happen?"
I have the answer to that one anyway. The parties switched places because the Democrats went from pro-slavery to anti-every-boundary-in-civilization. The Republicans stayed approximately in the same place.
In that sense, the Democrats went from being far to the right of us (if "right" means "for civilization as it was thousands of years ago, when slavery was the norm all over the world") to being far to the left of us (which means "against everything that makes civilization work").
The Republicans stayed the same. That's the "parties switching place."
‘Also they say “the parties switched places.”’
To which I reply, “show me the Republican owned slave plantations.” They can’t do that, which proves the parties have not switched places.
Neither Republican nor Democrat is purely anything. But it can be said that in general Democrats have always emphasized the group, the collective. In general Republicans has always emphasized the individual.
Thus Deomcrats are for, or against, ‘Black people’. Republicans are for, or against, Tim Scott, Ben Carson, W.E.B DuBois, Frederick Douglas, Harriet Tubman, Etc.
The same with Ethnicity. Historically Democrats at points in history, were for “The Irish”, “The Polish”, etc. Republicans were for, or against, the individual.
These are true generalizations. There are exceptions where Democrats acted like Republicans and Republicans acted like Democrats.
Imagine turning over everything you own to your servants for a year.
Better treat them well!