Typically the phrase 'someone's enthusiastic' would mean that someone is excited. However, reading the way it is being used here it appears to come across as sarcastic. This person is listing various tedious tasks that they have to complete that sound tedious and far from being fun. Therefore, in this case 'someone's enthusiastic' means that they are not excited about the work they must complete. Does this make sense? I can completely understand why this may phrase may come across confusing. I hope this helps! Please feel free to contact me if you have any questions.

A and B are discussing a list of tasks to do. (I assume that they are reporting on government statistics for a particular country, let's say it is China.) They need to look up the literacy rates in China. They need statistics on the schools. B suggests, why don't we look up the statistics in the encyclopedia (because that is a simple resource, easier than reading lots of books.) A says - no, the encyclopedia will not have current statistics, it is old. B then suggests calling the Chinese embassy to ask the people there. A says - "someone is enthusiastic", inferring the someone is B. And implying that calling the embassy is a more difficult method to find the statistics, so B must be really enthusiastic about doing this homework assignment to go to that much trouble! It ends with a adage: If something is worth doing, it is worth doing well. (basically it encourages a person to do a good job). Hope that helps! When I am kidding around with a friend, I will speak that way too. Like, if they yawn, I will say "Someone's tired". I could say "You are tired" but that 'stating the obvious'. Saying 'someone' makes them think a little, then realize it is they who are tired!