It's not difficult to know a bit about players - especially Championship and above - if you just pay attention. A lot of people seem to struggle to grasp that. Christie's a prominent Championship player and an international - anyone who watches a decent amount of football will have had the chance see him play.
The least you can find out without much difficulty is what position they are, what type of player they are and what their general level of ability is. After that, the more you watch and observe the more you'll know, although I will say that it takes more time watching to identify a player's weaknesses.
Would you rather people not post about other players unless they know everything about them? If it annoys you, there's always the very convenient option of ignoring the post, or this entire section of the forum for that matter.