The guy (obviously inexperienced, but this is entirely irrelevant) wanted to make a game and was intentionally led on to think they might receive help from one in a position of a higher claim to experience and profession, the latter being a later explicitly revealed lie. The problem with this is that the help was only offered because the one offering it wanted to confirm their negative suspicions, and to fairly aggressively kick the person while they're down in the end. This is not okay, regardless of who is participating.
I don't agree with what you did here. I know you don't need my approval, but I want to go ahead and explain my thoughts here anyway. I'm not going to call you a terrible person, I'm not going to point fingers and try and make you feel bad. I have no interest in speaking from a point of view of condescension and offence, and I hope to do nothing more in doing this than to try and elucidate to you a new manner of humane thought which may be wholly useful in general human discourse.
I want to first say that game design is a discipline, not a business. As it is a discipline, it is absolutely necessary to gain experience through practical application and pursuit of knowledge and practice in order to improve. To say that someone needs to be experienced before becoming experienced is very unfair to the person in question. One with little to no experience making a game will not have as much valuable insight into the process of making a game, nor will they have a fair amount of knowledge in its prerequisites, its commitments, and all manner of related things necessary for the creation of a significant end product. This is not a discouragement or a reason to stop, this is an encouragement to improve and a reason to try new things. For anything, you have to be worse to get better. I would suggest you consider this for yourself: when you first became interested in game design, could you answer the questions you asked this person?
Don't know where to plop this in there:
It's necessary to have failures. Failures mean you figure out what doesn't work, and you can discover where things need to be improved. Failures make you mature your outlook and execution. etc. essentially, it's not necessary to discourage someone with the threat of failure, as it will never be eliminated. Having those failures means you're learning, and you can never know what needs to be improved unless those areas poke (and oftentimes stab) through.
