Why did Holden feel bad for his roommate Dick Slagle?

Holden feels bad for Dick Slagle because his suitcases are much nicer and more expensive than Dick's cheap suitcases. In chapter 15, Holden mentions that he used to have a roommate named Dick Slagle, who happened to own inexpensive suitcases. Holden says that Dick used to keep his suitcases underneath his bed, instead of on the rack, so that they would not be standing next to Holden's more expensive suitcases. Holden mentions that he felt depressed that Dick Slagle was embarrassed to have his cheap suitcases next to his expensive Mark Cross suitcases. Holden felt bad enough that he even put his expensive suitcases underneath his bed, but Dick would always pull them out and put them back on the rack. Holden believes that the reason Dick put his suitcases on the rack was to make everyone think they were his. Holden goes on to mention that they only roomed together for two months before moving into different rooms. After telling his story about the suitcases and Dick Slagle, Holden says,

"The thing is, it's really hard to be roommates with people if your suitcases are much better than theirs—if yours are really good ones and theirs aren't" (Salinger, 59).