That's 100% reasonable. What's not reasonable is spending time to write a blog post in a tone that makes it seem like the product "is bad". The may not like it but the author wasn't a customer. It's the classic "I would buy it/pay for it if it only had XYZ or did/didn't do ABC." When in reality they were never going to pay for it, they just wanted something simple and free, which is 100% fine.