Isn't creating animation tightly tethered to physical realism as an inalienable rule at least to some degree kind of defeating the point of animation?

Enjoy what you watch because you like it. Don't try to watch anime in spite of it being anime; just watch something that suits your current tastes better. If someone feels like anime is for a younger crowd, it isn't worth the effort to 'change their mind' when there is so much media vying for our attention. Production of television and movies could stop dead right now and we'd all have a lifetime of media we haven't consumed yet; no reason to force a single show on someone.

//rant

You could argue that an elite Jomsviking could hold his own against a few disorganized pirates on tiny ships that reduce their number's effectiveness.