It's wrong to ruin people.
John is the head of a growing business and is trying to deal with a new competitor.
John wants his business to succeed.
John decides to find ways to differentiate his business from the new competitor and find a solid niche in the marketplace.
John is privy to information that will shut down his new competitor and uses it to do so.
Both businesses grow as customers choose which one fits their particular needs more.
The competitor loses their life's work and spends the rest of their days trying to ruin John's business in revenge.