TPNK flop raise?

[suited89]

Party Poker 3.00/6.00 Hold'em <font color="#0000FF">(6 handed)</font> link

only read is CO is loose

Preflop: Hero is BB with 4[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img].
<font color="#666666">2 folds</font>, CO calls, Button calls, SB completes, Hero checks.

Flop: (4.00 SB) A[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero ....

I usually raise in this situation to drive draws out behind me but I've seen posters recommend calling before and I'd like to understand why. Is it because of the small pot and the fact that we don't really need to protect our hand?

why the hell is my font red