Yes, it is a hoax.
The purpose may be different for each person involved and for some, it may not have been a scam.
But a manned trip to Mars is presently impossible no matter how much money is thrown at the project. The technology does not yet exist.
We can successfully send unmanned small probes to Mars because:
~Light weight probes can be accelerated with limited fuel.
~The travel time does not matter. Long duration slingshot maneuvers may be used. These reduce fuel consumption but extend the one way nine month trip to several years.
~Shielding from deadly cosmic rays is of limited concern.
~There would be no humans aboard that need constant food, water, pressure, oxygen, heat, medical care, recreation, exercise, cleaning etc. – and equipment for each.
~No fuel would be needed to lift off from Mars when the mission is completed.
~No fuel would be needed for a return trip; they do not return.
~If any of the thousands of vital ship functions fail, no life would be lost. The risk is therefore acceptable.