There's three ways to win points in tennis:
1. Free points (aces, non-returnable serves)
3. Unforced errors
Pushers have simply embraced #3 because they don't feel comfortable with #1 and #2. No shame in that.
Ask yourselves this: what if you played against a big-time ball basher, a total power hitter. However, you STILL won the match due to this power hitter's unforced errors. You didn't have to hit winners, he just couldn't keep the ball in play.
would you still classify the winner as a pusher? No, even though he won the majority of his points from unforced errors.
Some matches, you don't have to hit many winners. Some matches, your opponent will hand you the match. Other times, it's not that easy.
That's just tennis.