Yes, one has to careful about floating point, but honestly the article is not about that. Actually it is more about something where you do not have to be careful.
The article explicitly says while you might get away with it with some luck due to characteristics of the real world data, you do have to be careful.
From TFA:
"Now, in the real world, you have programs that ingest untold amounts of data. They sum numbers, divide them, multiply them, do unspeakable things to them in the name of “big data”. Very few of the people who consider themselves C++ wizards, or F# philosophers, or C# ninjas actually know that one needs to pay attention to how you torture the data. Otherwise, by the time you add, divide, multiply, subtract, and raise to the nth power you might be reporting mush and not data.
One saving grace of the real world is the fact that a given variable is unlikely to contain values with such an extreme range. On the other hand, in the real world, one hardly ever works with just a single variable, and one can hardly every verify the results of individual summations independently.
Anyway, the point of this post was not to make a grand statement, but to illustrate with a simple example that when using floating point, the way numbers are added up, and divided, matters."
