Alts. do not affect BTC, they simply dont. Now, everyone focusing their energy on alts. could be used to better promote BTC sure. But its like this, do little league baseball teams and games ruin MLB games and dilute the market ? no, they dont, thats what this is, its just a smaller game for people to keep busy with while BTC is gaining more popularity...
If I thought alt coins could kill bitcoin, I'd unload mine IMMEDIATELY while the price is more than zero.
Seriously people. Stop worrying over nothing.
Or, start an old rich white guys club and appoint a new Crypto Currency Auditor General.