Treating it seriously, I think that people are interested in growth because:

1. if we aren't growing, then due to attrition we are slowly dying
2. people seem to want a little bit more content, especially about niche topics that currently we have to keep going back to Reddit for bc that's where it is at
3. solving the problems inhibiting growth may make us better overall and our experiences here more enjoyable not only for new people but the existing userbase as well - so here growth is the diagnostic indicator of deeper phenomena

So it is not to feed the advertising machine and stockholder valuation, but even with the profit factor removed there are others that remain.