I think it was George Orwell who wrote about how sloppy use of language leads to sloppy thinking and he was, undoubtedly right. Grammar is an important tool, especially in the written language, but also matters too in speaking. If "wrong" grammar doesn't obscure the meaning of what is being said, then only pedants should protest even, although I hate to admit it, when perpetrated by television presenters. When it does obscure meaning, then it truly is a problem. However, Mrs DjangoDog is correct that most of these complaints are about vocabulary. While words do change their meaning over the years, we are losing nuances when words are used in a sloppy way, such as charisma to mean sexy, charming and popular, for example. Similarly, sayings and colloquialisms are also losing their distinctiveness. My pet hate is "in the firing line" for "in the line of fire" both of which are massively over-used but mean precisely opposite things.