Starship Technologies interview questions

The process took altogether 6 weeks, going through 2 of the 4 hiring process steps. I was invited to a first HR screening almost 3 weeks after sending my application. The second interview came quickly after, this latter being dedicated to discussing more in depth the specific alignment of my previous experience to the role to be filled. After this interview, I did not hear from them until I asked for feedback 2 weeks later. At that point I was told that the delay was due to having another candidate almost at the end of the process. This is how, in appearance, things went. They continued with another candidate after my step 2, which means they knew it was a preferred candidate also after his/her step 3, which means that no matter how I would have hypothetically passed step 3, I had no chance. In this scenario, the only possible reason for leaving me hanging, was on the off chance that this candidate backed out post-offer. Which is unlikely, given their following of all steps. The respectful thing to do should have been either a) letting me go after step 2, b) giving me the same chances of other candidates. This way of handling candidates feels quite unprofessional and definitely demeaning.