(Reuters) – Scotland captain Andy Robertson said supporters were right to air their frustration with boos after his side lost 3-0 to Ireland in a UEFA Nations League match. Troy Parrott, Michael Obafemi and Alan Browne scored as Ireland beat toothless Scotland, helping Stephen Kenny’s side win their first match in the competition. The defeat comes days after Scotland’s hopes of reaching Qatar were brought to an end by a 3-1 World Cup playoff defeat to Ukraine. “We weren’t good enough,” Robertson told Premier Sports. “We’ve now said that twice in 10 days. We’ve let the manager down, that’s what…