It's actually normal to expect fast withdrawals from casinos; I've experienced it myself. I don't mean to say anything bad about casinos, but it's a normal thing and can be a criticism for them to improve their speed.
Deposits need to be credited to accounts as soon as possible after they meet minimum confirmation numbers, and withdrawal requests need to be approved and proceeded automatically, not manually, and with quick processing time.
What you shouldn't do is, when a casino delays withdrawals or feels slow, accuse them of various things, like fraud, for example. That's overkill. However, if it's just criticism and suggestions, I think they're perfectly valid. After all, customers have the right to make suggestions.
Users can complain, make suggestion or anything else but they should do this politely. It is more acceptable and comfortable to receive complaints or suggestions in polite ways in business side and with users, in user side by making their voices in polite ways, they increase chances of being listened and reduce risk of bad treatments from companies.
Companies, if are legit, won't treat their users badly even users have bad mouths or contribute suggestion in impolite ways. However, as users we need to protect ourselves first and being polite is one of ways of self protection.