It has become commonplace in today’s society to crate-train your dog. We’ve been conditioned to think that it is a great way to housetrain a puppy, keep him or her safe while we work and to provide them with their own “den” where they feel comfortable. Crates in and of themselves are not evil. But, when they are used in place of proper training and human interaction, they cause more problems then they solve.
Puppies need lots of attention and socialization. Their little bladders need to be emptied frequently. Their minds need to be stimulated. They need physical exercise every day. Warehousing them in crate for 8+ hours a day will only lead to behavioral issues. A better solution when you can’t physically be with your puppy is to setup an exercicse pen or block off a small space such as a laundry room. This will give the puppy a safe space that will allow them freedom of movement and enrichment opportunities (Kong’s stuffed with peanut butter, etc.) while you are away.
While the United States allows the use of crates, other countries such as Germany, do not. It is technically illegal to crate a dog in Germany. Instead of crating, they believe in proper training and making arrangements to have your dog looked after while you work. https://together-magazine.com/magazine/24-counselor/75-dogs-in-germany-what-you-need-to-know
PETA actually has a good article on why not to crate a dog. That article can be found here: https://www.peta.org/about-peta/why-peta/crating-dogs/
Professinal dog trainer Jill Breitner published an article on www.dogster.com about why not to use a crate which is very clear to understand. https://www.dogster.com/lifestyle/why-i-dont-believe-in-crate-training