The point is that if you have to write a lot of glue code, chances are you have the wrong kind of glue.
Your chances of having the right kind of glue increase the more different kinds of glue you have to choose from. (Which is not my point, it is the point John Hughes made, but I certainly agree with it). Of course it isn't just a numbers game, for example you could have lots of different kinds of glue that are all horrible.
But if you have only one kind of glue, the chances of it being the right kind of glue in all circumstances are pretty low, regardless of the quality of any one kind of glue.
Your chances of having the right kind of glue increase the more different kinds of glue you have to choose from. (Which is not my point, it is the point John Hughes made, but I certainly agree with it). Of course it isn't just a numbers game, for example you could have lots of different kinds of glue that are all horrible.
But if you have only one kind of glue, the chances of it being the right kind of glue in all circumstances are pretty low, regardless of the quality of any one kind of glue.