Agree with you on this really,and dare I suggest your F-in-Law is perhaps in a bit of a timewarp on this,trapped in the post 1998 World Cup outrage.
After 1998 Beckham was public enemy no 1 after the stupid sending off v Argentina,and his 'image' for a few years after as a bit of a male tart did not help one iota.
In more recent times though he has come across a lot more stable character and better.Despite the high profile marriage that also caused some resentment, that seems stable and he has gone from the tart to a family man image.
In my view he has been overtaken in the 'poor role model' stakes by others,Rashley Cole ,a disgusting specimen,Terry and above all the Prostitute-Granny sh^gging Rooney who is probably the worst role model in the England set up.
(Beckham leaving Mancs probably also helped enable my dislike of him thaw as well by the way.)