The pastor of a Northborough Catholic church said the parish will no longer support the Worcester Art Museum after the museum publicly supported gay marriage. The Rev. Stephen Gemme of St. Bernadette’s said his parish will not ‘‘support [the museum] institutionally as in the past.’’ He did not specify how the church has supported the museum. Shortly after the Supreme Court ruled the Defense of Marriage Act unconstitutional, the museum congratulated the gay and lesbian community on its Facebook and Twitter pages and offered to host same-sex weddings. Museum officials told the Telegram & Gazette that reaction to the position has been overwhelmingly positive.