In a modern multi-cultural society, no reasonable person can assert that the entire country must observe a certain religious practice. (In this case, no gambling or drinking on Good Friday.)
There is absolutely nothing stopping devout Christians from not going to the TAB on Friday. Why should everyone else be forbade from spending their time however they see fit? The entire notion is preposterous and discriminatory. Bah!
Update: A number of years ago I was at a Pot Black when the police arrived to shut the place down. It turns out that they had a liquor license and (although they were not serving liquor) they could not operate on Good Friday. The police waited until everyone left. That’s nuts.