If we have known lots to be some sort of sacred activity that could act as a guide to help make some decisions after the outcome, can we not then classify or tag casting lots and drawing straws, as a kind of gambling activity?
Why not.
Casting lots and drawing straws are actually gambling in a way if you look at it on the other side of view. The both of them requires a random winner, which means the outcome of the activity is based on luck and not skill and if any money is staked while carrying the activity for anyone who gets the random number will be the winner then it can be said to be gambling. As long as betting is done in the act.