The guy in the Lear might have a deadline to meet, and was probably looking to conserve every pound of fuel. There is a big debate to be had, but it is certainly true that business aviation adds value to the economy, and arguably should get priority.
and
but I don't get reasoning which suggests the poorest pilot should have priority.
I don't get the reasoning which puts it the other way around. If the commercial pilot has a deadline or fuel issues then he needs to factor those in to his planning and flight operation and not depend on others to get him out of the mire.
In the UK the Rules of the Air set priority, followed by tactical adjustment by ATC (if being provided) for the overall good of all airspace users. Some UK ATC do however then apply a further 'priority' which is presumably based on who pays the most (some regional airfields which will hold you forever for a commercial aircraft still on a 10 mile final come to mind). In the abscence of ATC, then the Rules apply unless the pilots agree to modify them.