This is so strange that nobody responded when you said Sat Sri Akal. Can we know which Gurdwara was this? (Maybe by PM to avoid any issues pointing them out publicly) Maybe we can talk to the management committee and remind them that Sikhi is universal, and that visitors should be welcomed, openly, and not ignored.
At our Gurdwara here locally in Halifax, ANY new person (Sikh or not, Punjabi or not) are approached by the secretary and their name written down, and then after ardaas and hukamnama, when they do announcements, they list the newcomers and get them to stand, and then whole sangat says Waheguru Ji Ka Khalsa Waheguru Ji Ki Fateh to them, and then we tell them they are welcomed anytime they want to come to Gurdwara Sahib.