It takes a lot more to get back, though—Mars is a deeper gravity well (5 km/s escape velocity versus 2.4 km/s for the Moon). Then you are spending hundreds of days on the return journey, versus a week or less from the Moon. And humans are definitely going to want to come back, because to stay on Mars is to be doomed to radiation poisoning, and not on long timescales.

"Recent data from ExoMars Trace Gas Orbiter showed that on a six-month journey to the Red Planet an astronaut could be exposed to at least 60% of the total radiation dose limit recommended for their entire career."[0]

Maybe for robots, but I think human colonization of Mars without first mastering the Moon is very unlikely.

[0] https://www.esa.int/Science_Exploration/Human_and_Robotic_Ex...