Tomatoes have a lot of acid in them, but they can still be sweet and flavorful. But even the ones you can get at the u-pick farm are flavorless and too pithy.
Does not change the fact that at the time the author was talking about in many places tomatoes were eaten with cream and sugar because they were full of acid rather then sugars.
People forget how much foods have been altered to suit our tastes in the past 100 years.
Corn and tomatoes are two that are much sweeter.