While I think that it's safe to keep your coins on Freebitco because this website has proven to be trustworthy, honest and fair since 2013, we still shouldn't forget that not your keys means to not your coins. If I were an early adopter who bough bunch of bitcoins when price was low, I would simply hold 10-20 bitcoins on freebitco account to cover my monthly expanses and more.
If you say not your keys not your coins then why you suggest to keep your coins here? You are contradicting your own opinion so there no context behind your statement about that. If you said Not your keys not your coins suggest the user to safe keep his coins to the wallets where they hold their private key since from that they can assure their safety.
I don't mean Freebitco.in is a bad site since they are really so good for providing good experience to their gamblers but we are talking about safety here so much really better if majority of people decide to hold their coins on much safer place.
I think the idea is that "this one could be an exception so far, but it is still to be secure then sorry" as in yeah this place hasn't shown any reason to doubt them, but if anything happens to them, it's your coins that will be gone.
However, I do trust them, I do not agree with him, I trust freebitco.in enough that I have been saving up money at any given moment and ALWAYS put my money here, not to just gamble or anything, I deposit here for the returns and that's the most important thing. I believe that there aren't any other place that could give me a good return like this place does that I can trust as much as this place, which is why I think it's quite important to keep it going as good as I could hope for, that's the most important part.