Deletionism (noun deletionist) is a Wikipedian Philosophy advocating for deleting unpopular or famous stubs. Deletionists want Wikipedia to be similar to a paper Encyclopaedia. So, Wikipedia would have only a few, very long, articles.
Deletionism is quite irritating. They don't support whether or not the information on Wikipedia is valid, or can be expanded, they take the easy way out. They delete it rather than edit it!