STOCKTON — An outspoken critic of Michael Tubbs has asked a federal court to declare the mayor’s decision to block him on social media unconstitutional.Motecuzoma Sanchez, a one-time candidate for Stockton City Council, filed a complaint in United States District Court on Feb. 22.In the complaint, Sanchez said he repeatedly has criticized the mayor on his official Facebook and Twitter pages, resulting in Tubbs deleting his comments and ultimately [...]