My take on the Mayor endorsing candidates...

If you think a while on how our system is set up, all of the Commissioners and the Mayor are elected by the same people.  No Commissioner is elected just from the district that they serve.  Other than running meetings, making a little more money and being the titular head of the city, nothing really distinguishes the Mayor from a Commissioner.  The Mayor position does not carry an automatic pledge of neutrality.

There is a long record of Commissioners supporting other candidates.  Case in point:

So showing preference for a certain candidate has been done for a long time by sitting City Commissioners.  Our last Mayor chose not to engage in the practice so Mayor Varela's current endorsement of Blockson and Maxwell seems new, but it really isn't.  The argument that somehow this is inappropriate is more sour grapes or wishful thinking than anything else.