I have taken Levaquin several times and have never had any problems with it. Keep in mind that it is entirely possible for ANYONE to have a severe or deadly allergic reaction to ANY drug, food, or any other substance, for that matter. Banning drugs, foods, or other substances because they could cause a life-threatening allergic reactions would not be a good idea. ALL medications come with the risk of severe or even life-threatening allergic reactions. Some medications, such as penicilin, may save some people's lives, while those same medications could cause life-threatening allergic reactions in other people.
You question why you were given that drug. You were given that drug because your doctor diagnosed an infection that could be treated with that antibiotic, and since you had not had an allergic reaction to it in the past, he or she saw no reason not to prescribe it. (Even if you've taken a drug several times in the past with no problems, it is possible for you to become allergic to it at any time.)