So basically he lost because...
1.) He had a weird (or should I say bizarre?) last name
2.) He came from a less populous county
What a stupid, stupid reason to lose. I credited Pennsylvania Democratic voters as having more intelligence and not being THIS low-propensity.
If you're clueless about an election and the candidates running, sit out the primary and let the more well-informed party members decide instead of letting the election come down to arbitrary factors like this.
There was also some chatter that he blew off a few events and was generally a dick to people because he expected to be coronated in the primary rather than putting in the actual ground work, whereas McClelland showed up to events and talked to voters. Take that with a grain of salt, but that is a much more logical explanation than just plainly the county/last name theory.
