People don't always lose, if they do follow the relatively simple ways of gambling the wins/loss shouldn't be more than 60 or 70 to 40 and 30, People lose on long term due to house edge, Agreed, but not always losing or else nobody would gamble, We do all-in and hence a single bet can mean a loss to a whole deposit. Also regarding the question, because gambling is addictive.
Gambling is a very risky thing thats why people should not gamble everything that they have. I know that people want to get more money, I was once like that but I have lose alot to finally realize my mistake. We will still play even if we lose because gambling is very addicting and I cant get out of it still until today