You're likely to hear a variety of different opinions about how to conduct genealogy research. There are some people who seem to believe that online research is somehow not as good as research that is conducted onsite at a courthouse, cemetery, or register of deeds office.
Personally, I think both methods are valid. While there's nothing quite like finding an actual record that you can make copies of to add to your files, conducting research online certainly serves a valuable purpose for genealogists everywhere.
Before the wonders of the internet provided me with the ability to peruse decades of census, marriage, birth, and death records, my research options were strictly limited to a fairly small geographic area. For the most part, I was only able to conduct research in locations that were within a reasonable driving distance. Now, I'm able to make a significant amount of progress that likely would have taken me years to accomplish the old-fashioned way.
I think that one of the major issues some people have with online research is the number of individuals who blindly add ancestors to their family trees without taking the time to properly evaluate the evidence on which they're basing their decisions. They find a name that seems right and add it without examining things like dates, geographic areas, or family relationships. In other words, they're not really researching; they're just looking to add names to their family trees.
Whether this type of activity is due to laziness, carelessness, or indifference, I don't know. As someone who conducts research in-person (when I can) and online, I feel very strongly about the importance of being able to cite resources for each individual within my family tree. The more evidence, the better. It doesn't matter whether I share my research with anyone else or not. I want to have proper documentation for my own benefit as a researcher.