I've never reloaded before but I plan to only reload pistol ammo for the time being in 9mm and 45acp. Hopefully in at least 2 more calibers by the end of this year

I don't shoot a lot but that's partly because I don't want to spend so much on ammo only to shoot for a short amount of time. Even then I still don't really see a downside to having a good stock pile of ammo, especially when relatives come to visit or friends want to do some shooting.
Here's where I'm looking for some opinions. I've made my decisions but they can always change for a better one.
Looking at different presses I've decided to go with a Dillon SDB for my handgun ammo needs. When I decide to get a rifle, I'll shoot around a bit, collect my own brass, feel the hurt of the ammo prices and get a single press to help me concentrate more on this type of reload as it seems a lot more tedious and specific (brass trimming etc.). I don't have much brass so my plan is to just buy clean brass and load those then save and stock up on them after I've fired them once. Then clean and reload them and as far as a cleaner I've also decided on a wet brass cleaner, I won't need a huge one so the $100's range should fit me nicely.
At the moment I don't care too much for spit shinny brass, I just want to make sure it's clean and doesn't let out any dust in to the air for me or my family to breathe in as I'm reading what can happen with dry tumbling and I'd rather deal with the dirty water and SS material than the other stuff.
One thing confuses me a bit though:
I see some vids of individuals using their reloader to resize and deprime their brass. Have they cleaned it with a primer still intact or are they just reload dirty/spent casings?