Moderation in bad things is better than no moderation in bad things but it still does not make them good.

The problem I have with the moderation argument is "what amount is moderation?" Take sugar consumption. A couple hundred or so years ago about 5 pounds per year was average consumption per person. That meant some ate much more, some less or none. Yet today it is around 100 pounds per year. Again, some significantly more and some (me for example) a lot less. So what is "moderation"? Is it less than 5#? Is it less than 100#? 75# is still a lot of sugar per year yet that could be considered moderation by someone who had been eating 125#. Does that mean that 75# is ok and will not harm a person but 100 will?

Hard to say. A smaller amount of something that is bad for a person would stand to reason being better than a lot of it. So moderation has its merits. But I doubt if it will be optimal and in many cases even acceptable.

Same goes for seed oils. A hundred fifty years ago no one ate any significant amount of seed oils other than the amount of oil in the seeds they ate in food. Today a significant portion of our calories daily come from seed oils contained in almost all processed and manufactured food stuff. We are getting thousands of times the amounts people would have been getting two hundred years ago. So what is moderation? What was eaten back then or what was eaten today? Neither or some where in between? 
I will not bother to put up a chart of heart disease compared to the two charts below. After all, correlation does not prove causation. But it may raise questions.