From an FT editorial on the EU's likely decision to exclude Sri Lanka from its GSP Plus trade preference program:
Using trade as a strategic tool makes the global trading system hostage to endless political posturing and negotiating games. Governments should grant trade preferences on simple, fair criteria, largely based on the poverty and vulnerability of trading partners. Trade deals should be a means for poor countries to haul themselves out of poverty, not a tool of foreign policy manipulation by their richer counterparts. Sri Lanka’s exporters have used their access to the European market well. They should keep it.
Arguably, what the FT advocates is pretty close to what WTO rules require. (Although, as with most laws, there are counterarguments as well.)