Sting and Springsteen are pop musicians, nothing more.
Pop is not a style of music but a process by which singers and songs are packaged and sold, or defined and showcased, if you prefer. This process consists of taking elements of one or more musical styles (rock, jazz, blue, C&W;, etc.) and combining them to complement the singer and song being merchandised (or "help him convey his message").
Any elements of the style that would tend to distract from the singer or song are discarded (i.e., "boring" guitar solos, "unmelodic" blues or jazz tonalities, intrusively heavy rhythm sections).
The pop process is not necessarily calculated or totally mercenary, but it rarely adds anything to the styles of music it uses--there are almost no great or truly innovative pop musicians, only tasteful borrowers and skillful synthesists.
You can bow to your pop idols if you like, Mr. Hilburn, but don't call them "rock"! Rock is a true style of music, not a marketing tool, catch-phrase or attitude, and it has definite characteristics, among which are: blues tonality, loud volume levels, bands based around a guitar-bass-drums axis, hard "boogie" rhythms a la Chuck Berry-Eddie Cochran and lyrics dealing primarily with sex, partying, frustration and other adolescent concerns.
Important rock groups include the Rolling Stones, AC/DC, Aerosmith, KISS, Alice Cooper, ZZ Top. Recent examples of note would be Guns 'n' Roses, Bon Jovi, Hanoi Rocks, Tesla and Poison. Like it or not, it is bands such as these that set the standards for rock, not pop stars like Mellencamp or Springsteen or novelty acts like Thelonius Monster and Jesus and Mary Chain, however much they may appeal to music writers who find actual rockers too crass and intimidating to deal with, but are unwilling to admit that rock has passed them by.