1) System P is big-endian. Apparently big-endian-ness completely confuses weakly-skilled programmers to the point that their brains go "tilt".

2) Practice shows that unfamiliar environment of AIX greatly confuses the attackers, again to the point that they just do some damage and leave instead of stealing the data or wreaking some skillful havoc.

I have years of practice in this field. Originally when young, I thought that it shouldn't be the case either, any person who is intelligent enough to program should be understand how to number bytes in a multi-byte integer. But the practice shows otherwise. For the confirmation of this fact go lookup various discussions of endian-ness on this forum and the source code for "getwork" in the Satoshi's client.