What if other teachers behaved like Snape?

[Walter Gruver]

No: HPFGUIDX 101402

Justine responds:
> Draco doesn't know exactly what was behind Harry's 
> fainting spell, so he may have little reason to think 
> seeing a "scary" Dementor won't cause Harry to faint 
> once again.  But, then again, of course, Malfoy can 
> be an insensitive little git... perhaps the thought 
> never occurred to him at all.  It could merely have 
> been an impulsive prank...

Walter:
Malfoy's insecurites don't run very deep at all.  Everything that he feels and thinks is pretty much on the surface.
 
It's fair to assume that the Dementors checked all the cars on the train and that most of the students experienced the same emotional response that Ron expressed to Harry.  Even assuming that, Draco isn't likely to connect the feeling of depression or unhappiness with the Dementor's presence and thereby come to the conclusion that the Dementors had a more drastic effect on Harry.
 
I'd wager that in Malfoy's constant jealousy of Harry's popularity in the Wizarding world that Malfoy has never given Harry's emotion trauma a second thought.
 
As JKR writes him, he probably is miserable on a regular basis when he is not at school.  Any sense of happiness or contentment he might experience at school is only at the expense of those he truly dispises or regards as inferior (which quite frankly is just about everyone).