They are not "following orders", they are doing their ( unpaid ) jobs - saving people from drowning. They don't ask for ID before acting, they just risk their own lives to save others.
If you want to aim you ire at people "bringing" these migrsnts into the UK, do so at Border Force - less than 6% of people crossing the Channel are picked up by the RNLI, who then pass them on to the authorities as they are landed, over 90% are landed by BF. Or possibly at the French, who escort them out to the edge of their territorial waters.
I suppose you would be happier just letting these people drown.