It sounds to me that they're trying to work around their own beliefs which is just weird to say the least.
I'm not a muslim and don't consider gambling a sin but I believe that you shouldn't knowingly commit the same sin every day even if you pray and do something good right after commiting that sin.
It is true that we as Muslims constantly commit sins worse than gambling and we do not care about those sins. Just as praying five times as a Muslim is obligatory, if we miss any prayer without reason, then we have committed a serious sin. So I promise not to commit all those major sins without looking at gambling.