Addiction and using simple pleasures to fill the hole of depression is certainly a problem... however that issue transcends any individual pleasure. People can be addicted to TV, video games, political news, and even books.
Further, gambling is essentially a zero-sum game. The house always wins, equal to how much you lose, and pretty much every gambler loses besides the one or two rare examples who strike a jackpot the first time they ever play and then never gamble again. In contrast, buying a video game is a transactions both parties are normally expected to benefit from equally, and a video game's single player mode is expected to last at least 10 hours at a minimum nowadays not counting online play that lasts essentially as long as you want, while gambling machines need a constant input of money that adds up to much more over time. Even comparing to coin-based arcade machines, a session on one of those will last much longer for the price, and even in the microtransactions that have become common nowadays you at least end up with something more than the screen flashing some bright lights for a few seconds. So overall on this point, it seems to me like a gambling establishment is necessarily exploitative while a video game publisher isn't.
You or I might value a video game more, but some people who gamble actually derive utility from the games themselves (and from a purely scientific standpoint, even a near-miss in gambling results in the release of dopamine [1]).
[1]:http://www.nature.com/npp/journal/v36/n5/abs/npp2010230a.htm...
I like going to a casino once a month with friends, always with a preset $50 limit. That translates to hours of great fun, food, drinks. I'll start the day with poker if we're planning to stay for a while, I'm good enough to turn a profit (which I spend on other pure-luck games). Other times I'll just suss out the slot machines while watching a game at the bar.
On the other hand, I never play video games... I just find them universally boring. $20 for 10 hours of gameplay sounds like a waste of time and money to me. However, I do understand why other people enjoy video games.
At the end of the day, I've seen self-destructive gamblers pumping the slots and subtly self-destructive gamers pay2playing... as well as responsible gamblers and gamers. To each their own.
The main practical differences to me are that the gambling industry is more nakedly exploitative, more reliably engineered for addiction, and more frequently destructive to people's lives.
But I think parts of the video game industry are headed in that direction.
When I watch my brother and my nephew playing, say Battlefield 1, they are visibly having fun. They bought the game once and are getting many hours of enjoyment out of it, a few at a time. It seems a reasonably healthy pastime to me.
But then I'll watch people playing Zynga-ish games. They don't look like they're having fun. They look like people playing slots: low affect, compulsive, grinding away at something that never really satisfies.
So personally, it's not that I don't like gambling specifically. A friend's low-ante poker night can be a good time. It's that I hate profitable exploitation of people's weaknesses in a way that leaves them worse off. Industrial-scale gambling and shitty, addictive games are both in that bucket for me.
What separates responsible anything from anything else? Nothing at all.
Anything can be addictive if it lights up the pleasure centres in your brain and you use that to fill the hole of depression. Computer Games. Drinking. Gambling. Smoking. Drugs. Adrenaline. Shopping. Hoarding. None of these things will fill the hole in your heart or fix depression. They're just distractions. I used to be married to a drug addict. Her father was an alcoholic. I knew and spent time with dealers and other addicts. I have direct experience with that. I spent 6 years of my life dealing with that. So I have more of an understanding of what depression and addiction can do to your life than most.
Sure, I do have a lot of ignorance when it comes to casinos. But I have been in them, I have seen people gambling responsibly. I have gambled responsibly. You're right in your perception that I don't get enjoyment out of it. In fact, the act of gambling doesn't light up the pleasure centres in my brain. The wins and losses are academic. Clinical. But this goes far deeper than that. There are tons of things I don't get enjoyment that I have tried that don't give me this feeling about the participants.
I am an empath. The moods of people in my proximity greatly affects my own emotions. I frequently have problems untangling which feelings are mine and which are someone else's. I can be feeling light and happy and walk into a room where someone is in a bad mood, and like The Pink Panther, the cloud rolls in and my good mood is gone. I am under a cloud. It's usually not as clear cut as this, nor as easy to decipher that this isn't my mood. This is off-topic, I'm just trying to give you a sense of the fact that this isn't borne out of my own emotional preconceptions. This is borne out of the people around me, not the casino itself which I'm actually largely indifferent about. Just as I'm indifferent about people who smoke pot, enjoy computer games, find enjoyment shopping. This isn't about the activity. This is about the emotional well-being of the people in my proximity.
I agree, there are many people that do gamble responsibly for fun, they go out, they spend responsibly, they enjoy it for what it is, they walk away. I don't get this feeling from those people. These are healthy, emotionally balanced people. They're not trying to fill a void in their soul. They're just out having fun. Perhaps I'd enjoy their company. I can't say because I don't know them.
However, there are such a significant portion of people that aren't like this in casinos that it's impossible to ignore - to the point that I literally feel like it's suffocating me and invokes my fight or flight response. It makes me want to leave. If you suffer from claustrophobia, you will understand they symptoms profoundly. If you're put in a room you can't get out of, you suffer a physical and emotional response. You may be able to hide it from those around you. You may be able to look to everyone else like you're okay. But inside, you're suffering from an increased stress response, you feel uncomfortable, you feel hot, you might start to feel your muscles tingle or vibrate, you feel trapped, you feel like you need to escape, you're acutely aware of where the exits are and your shortest path to them. Add to that the fact that the hopeless lost void I'm feeling in those around me and that's how I feel in most of the casinos I've been in.