As noted above, Fire in the Sky is done in conjunction with Orrville's annual July 4th festival, and it just happens to be in the middle of the week this year. I assume Joe doesn't have much say on when that festival takes place, though no doubt a good share of the success of the festival is tied to all of the people being in town for the tournament.
Keep in mind that you have to apply for and be accepted into Stingrays, and that it is very difficult to get in. I don't have the data, but my assumption is that most 13U teams don't even get in unless they're from a high profile organization, had a very successful 12U season, and beat some other high profile teams along the way.
There are pros of each tourney, arguably the two best in Ohio and even the Midwest region each year. If I had a team whose goal it was to get players recruited by college and I could get into Stingrays, I would probably have to go there, but I would hate the thought of missing out on Fire in the Sky.