Hehe, the goat-man calling people sheep.
Anyways, that's just something you're going to have to deal with when you're the Alpha baby. Seriously however, it sounds like that gent was a touch bit of a tool. The way i see it, people collect what they want to collect. I've had numerous ideas based on armies I want to do, an all samurai/ninja/Striking Scorpion Eldar Army, the Word Bearers from First Heretic using an SM codex and posessed models as the Command Squad, recreate Black Hawk Down in Guard, an all Scourge/Helion Dark Eldar army, yet due to funds, and a strict discipline of "finish what you start", i only let myself do two armies at a time. At the minute, it's my Space Wolves and Mantis Warriors, the former because i've always done them and have various ideas i want to try before i retire them, the latter as a long term project to make on of the Badab War Companies.
Now, does that make me a sheep because i'm doing two armies i like? Vikings, and Dust Warriors?
Nope, it just means i have a different interest to that gent. I'm not a fan of Tau, i'm not a fan of Dark Angels, i'm not a fan of Orks, i'm not a fan of Necrons, should i collect them because they're different? Or should i collect what i like? I have an interest in Roman and Greek history, and so base my WoC around the militaries of those time periods, because they're the best fit, i shouldn't have to worry about what army is "in" at the minute, or look at what everyone else is collecting before i decide what i'm going to do, i'm going to do what i'm going to do, regardless of what other people are doing.
I also think that Wyddr has a point. Marines get a bad rep because the majority of people play them, and so the proportion of least skilled/most annoying will seem to be more in the Marines than other races.
I reckon that the guy who said that is pretty hipster, and listens to music that you probably havn't heard of, and refers to us common folk as proles.