I think the "loose shoes" may be intended to indicate laziness, shiftlessness, unseriousness. That is, being overly concerned with comfort rather than utility. Also the contrast of "loose" with "tight" adds a little poetry to the line as a whole. That's my take.
Flag on the play, uniformed player on the field! LOL, so don't get offended. It is an observation that certain black men would dress up to go party, and one of the dress items was a pair of good-looking, pointed, shoes. These were not the ordinary shoes, they were for dress and were uncomfortable. Loose shoes of course were more comfortable, hence desirable for day to day wear. The juxtaposition of loose and tight was was made the joke funny.