You have the option of rearranging. your 401k investments where you can choose to invest in individual companies instead of the grab bag fund where the managers invest in a little bit, parceled out to many companies where they give equal weight to investing in Intel, Dell, Microsoft and Apple. Which is a horrible deal because Apple, for example, has outperform those three companies by a wide margin over the last 20 years.
Note: you have to go out of your way. to make this happen. Most funds prefer to dump everything together, so they don’t have to make individual tough decisions.
not all those 401ks offer the level of granularity you're espousing, i've been looking to divest certain holdings based on religious views and can't figure out how to blacklist certain companies directly.
edit: i'd like to see a situation where an employee's private 401k is liberalized to the point where we can select not just the offerings but the offeree.