Like so much with him, Quixote's armor is his own creation. Quixote's armor is of his family name and something that is homemade: "The first thing he did was to clean up some armour that had belonged to his great-grandfather, and had been for ages lying forgotten in a corner eaten with rust and covered with mildew." Quixote recognizes that the armor needs cleaning so "he scoured and polished it as best he could". Quixote recognizes that the visor on the helmet is not effective. In typical Quixote fashion, he constructs his own solution, as if willed by his own desires:
This deficiency, however, his ingenuity supplied, for he contrived a kind of half-helmet of pasteboard which, fitted on to the morion, looked like a whole one. It is true that, in order to see if it was strong and fit to stand a cut, he drew his sword and gave it a couple of slashes, the first of which undid in an instant what had taken him a week to do. The ease with which he had knocked it to pieces disconcerted him somewhat, and to guard against that danger he set to work again, fixing bars of iron on the inside until he was satisfied with its strength; and then, not caring to try any more experiments with it, he passed it and adopted it as a helmet of the most perfect construction.
Given how Quixote has committed himself to "righting every kind of wrong, and exposing himself to peril and danger from which, in the issue, he was to reap eternal renown and fame," it makes sense that his own armor represents "the most perfect construction." From this, Quixote is able to set out on his voyage of the knight.
The remaining answers are based purely out of opinion. I would suggest that Quixote is continued to be held as a hero precisely because he is out of touch with reality. Quixote is out of touch with reality, and this is what enables him to envision what can be as opposed to what is. When we consider that some of the worst crimes in humanity have been perpetrated because individuals have been bound and tethered to the world in which they live, Quixote's heroism lies in how "out of touch with reality" he actually is. Carlos Fuentes argued as much in suggesting why Quixote's appeal is lasting:
Don Quixote is a great hero of fiction and of philosophy—I think of thought as well—because he will not give up the idea of unity in order to understand the world of diversity. Yet he must admit the world of diversity in order to admit himself, since he is only “Don Quixote” because he is read, and he is read by a multitude of readers, not by only one reader.
Quixote is "out of touch" with the world that tells him that his vision of being a knight is dead. He acknowledges this reality and yet does not allow it to permeate his own vision of himself. Quixote never punishes anyone who tells him that his quest is fraudulent. He remains true to his vision of being the knight. There is something heroic about individuals who strive in the face of forces that outwardly question or denigrate. When we consider some of the greatest of human beings and why they are so meaningful, Quixote's notion of heroism is evident. He is out of touch with reality. As a result, this becomes the secret to his identity and his greatness.
I think that the idea of "tilting at windmills" can be said in a derisive manner. Yet, I think that Quixote's fight against the windmills is a reflection of conviction. There is a relentless pursuit of the monsters. Even when he is confronted with how they are windmills, Quixote is always vigilant about how they could "change" at any given time. Quixote's tilting at windmills is a testament to his imagination and his capacity for dreams. Quixote's imagination and moral sense of understanding seek to make the world better, righting wrongs that have been committed. It is an understanding that strives to make the world better than it was. It is in this light where he continues to attack windmills. To tilt at windmills is a direct reflection of the tradition that Quixote initiates. Such a pursuit of dreams represents respectability and honor. I think that this is where such a charge has to be see as a badge of honor for it comes out of the belief that "the fight goes on, the cause endures, and the dream shall never die." Gabriel Garcia- Marquez once said, “It is not true that people stop pursuing dreams because they grow old, they grow old because they stop pursuing dreams.” Quixote's tilting at windmills shows that he will never get old because he will always be in pursuit of his dreams.