Well, I agree with the Moderns insofar as what they were rebelling against was the sort of moralizing sentimentality that preached rather than evoked. I'm not by nature a very sentimental person, and I tend to view sentiment in poetry as akin to cliché: in other words, a sign that stands in for a genuine feeling. Sentiment is meant to evoke superficial and pious feeling, not gut-level feeling. It's very safe, all very pastel. The Moderns in their rebellion came up with one solution. But Robinson Jeffers and some other West Coast poets came up with entirely different solutions—and Jeffers is one of the least sentimental of poets.
I pretty much agree, Art, though I would draw a distinction between sentiment -- which I think is perfectly natural -- and sentimentality, which I think of as emotional reaction to something that is out of proportion, a kind of emotional exhibitionism. I am definitely not sentimental.