It is a quirk.
You can set all your domes that are not supposed to take in tourists to reject tourists by downthumbing the quirk in the filters.
Then you build a tourist dome in a nice vista location, put enough housing, open air gyms and parks for comfort inside, place a stockpile of food outside the airlock and place a landing pad next to it. Then you call a rocket there and tell it to take tourists. Set Tourists as the preferred quirk in the tourist dome‘s filter. Also prefer unspecialized people and reject any other profession. Tourists are always unspecialized. It also helps to reject children and seniors, since tourists most often are young, adult or middle aged.
For your convenience you should consider using the mod „automated tourism“.
Unless you have the breakthrough for automated service buildings, you don‘t need to provide them for tourists. Their comfort will be high enough, even with no service building inside their „resort dome“.
I usually go with one basic dome, 1 arcology, three basic living quarters, two parks and one open air gym for a tourist dome. Works like a charm.