Semantic Web - Web Cleaners - BS job or OCD?

I spent recently some time with computer scientists and information management experts.
Our conversation dived in the future of the web : the semantic web
Imagine you could layer by layer add different perspectives from an initial research. The computer would not photograph your word to find it anywhere else but would try to understand the meaning and context in which this particular word is used and find all associated data.You are the one who is determining the meaning and context.
For example, you are interested in a particular drug used to heal people from a particular illness. Not only, can you enter the name of the drug, you can also search whether there have been indications of allergy in certain case using this drug from scientist team from a country across the world. The possibility are endless and possibility for collaboration too.
However, what happen when the data is wrong, what happen when there is a mistake, what happen when there is a black swan in the pond. You are looking for information on Shakespeare and you find in the sea of the semantic associations, the name of a famous italian poet from the 15th century and you wonder why has he been invited to the party? THERE is A BUG!
Cleaning the web seems to be the only way. Who? How long would we clean the web for? When I think that no one really want to clean the sea...How much would we pay those cleaners? Would cleaners have the authority to delete content? Which criteria would they use to indicate whether the information is relevant or not? I have so many questions and worries.
I am smiling. Uncertainty, fear and doubts are creeping in and the beginning of a new obsession is appearing...
Could we become obsessive with cleaning the web?