Klaviyo interview questions

The interview process was quite lengthy. Submitted my application online and was contacted by the hiring manager via email with a few open ended questions to show my interest in the job. After reviewing my answers, the hiring manager said she'd like to set up a time to speak with me. Did a brief phone screen and then she had me do an assignment in the software which took quite a few hours. I'm usually hesitant to do this kind of work for companies I haven't even been hired by yet, but I went and did it anyways. After submitting this work (which had several steps and took me 6 hours, by the way) they said they'd like to bring me in for an interview. I interviewed with 4 different people over the course of 2 hours and received an abrupt, 3 line generic rejection email the next day. I get it, I may not have been a fit for the job - but to have an interviewee do that ridiculous amount of work to reject them like so - really didn't sit well with me. Didn't like the vibe I got from this company at all.