It's also funny the issue of prize money is the topic again when Wayne Ferreira recently claimed Fed was involved in making the slams pay more from way back in 2003 but because the ATP adopted a similar position the movement stopped temporarily (it's in a NY article by Christopher Clarey where he talks about the consecutive appearances at Slams).
and in the meantime as the French Tennis Federation and French newspapers keep on blaming Federer for being the only responsible for the prize money which they have to increase, even claiming that he asks for that only for his individual interest ...
Yes, that's how things go : it's never good to take political responsibilities for one's popularity in the eyes of emotional people.
Janowicz like a few other players just saw Nadal shout for a boycott, whereas Fed was cautious and asked the players to cool down and that boycott threats were a bit premature, and in his mind he has this emotional picture printed, and he judges according to it.
That's emotional primary judgment and he was not the only player reacting like that.
It was actually good politics from Nadal, as far as his own popularity was concerned, except that his goals finally failed for a two-year ranking system despite the support of most top-10 players of the time (his call to change the calendar and have the WTF right after the US Open seemed to be progressing until recently where the recent news have not looked as encouraging for that plan) ... but for the goal at stake for lower-ranked players, the slam prize money, Fed took a bigger part ... even though clearly boycott threats helped the claim a lot.