You shouldn't really take it personally. The problem with online communication is that it lacks all of the nuance of expression. What you may have intended as helpful advice, he may take as criticism, etc.

The part about responsibility is this: what do you go into the game expecting out of your peers? There are no hard and fast rules on what to expect out of a guild. Some guilds are friendly and carebear and helpful. Others are goal oriented like raiding or PVP where you're expected to pull your own weight leveling wise and only participate when you're sufficiently geared.

If your guildmate is accusing you of being critical and unhelpful, what has he done to help other people? Why does he feel entitled to help and coddling from you?

And it's not just in a material sense either. Some players don't want advice on how to improve their playing. They may not even care, and that's perfectly valid if it's how they want to play. It's a game, after all, not a job. But then they shouldn't expect other people to hold their hand or make up for their deficiencies when grouping either.