Maybe they feel totally discouraged or they feel that it would take up too much time to revise. What they fail to understand that if an editor has taken time to make suggestions, they should try again. Giving up should not be an option. Writers have some choices. They can revise their article exactly as suggested. They can use some of the editor's suggestions to make their work stronger. They can submit the piece to a different editor, revised or not.
Keep in mind that many times, rejections are subjective. And, few writers are immune to them. Famous authors like J. K. Rowling and Theodor Geisel had their share of rejections. Rejection rarely indicates that your work is not good. In some cases, a rejection just means the editor already has a similar piece on hand. Other times, a writer might receive a rejection if the concept is too advanced for the intended age group. A rejection might be given if the article has failed to meet the guidelines.
The key to remember when you receive a rejection is: don’t stop writing. Writing for children means you've got to persevere. After the sting of rejection has worn off, get back to work. Learn from the rejection, especially if an editor has offered ways for improving the piece. Strive to improve and submit your work again.