A taxpayer-funded Texas waterpark is getting splash-back for a “Muslims only” event next month after a local Islamic group rented out the facility. A flier for the DFW Epic Eid event on June 1 noted three times that attendance was strictly for Muslims — and modest swimsuits are required. “Seems like a civil rights violation,” one outraged commenter said. “Should we expect a ‘Christians Only’ day?” another commenter asked. Radio host Dana Loesch asked, “How is a taxpayer-funded, city-owned entity allowed to discriminate against non-Muslims at a public water park?” The initial flier for the event noted three times at it was “Muslim only.” After the backlash, the organizer of the event, Aminah Knight, told The Post that she is backtracking on how she is advertising it — “to make it clearer that this is a modest dress-only event centered around celebrating Eid.” The third-annual event is being held at Epic Waters in Grand Prairie, outside Dallas, a massive, 80,000-square-feet indoor waterpark opened in 2017 at a…