Yes. To be clear though, only the multiplayer component is free. They also give one of the three solo campaign missions for free. So if you had nothing, you'll start with the Terran solo campaign. If you want Zerg/Protoss than those are still paid. If you already owned the Terran campaign then you'll get the Zerg one for free. And so on and so forth.
Basically it drives up people into multiplayer of SC2 and gets them interested in paying for other micro-transactions or solo content.
If you want to be the top 1% in any game then I guess you could always argue it's too late to start. There's competitive and there is competitive.
You can be competitive like running your local 5k but perhaps you can't be competitive and run in the Olympics.
You'll find all levels of competition, which is why there is a really stratified ranking system in StarCraft 2.
Or... you know you could just play the game for fun and/or play the single player aspect. If it's your first time picking it up, then you'll get the Terran campaign for free and you can see if you want to play any more than that.
meh, Blizzar....i mean Activation can gofuck a suck. What they did those HongKong guys was pretty crappy as well as launching mobile cow clicker games at a PC/Console gaming convention. ON the other Hand i did buy their releases on GOG. I can at least support friendly move like that. so i guess idk.