LinkedIn interview questions

I was contacted by a recruiter in early December regarding a role at LinkedIn. After an initial recruiter screening, I was put through for a hiring manager call. While on that call the HM mentioned putting me through to their hiring board where I'd have to do an assignment. I was asked to make a full content plan based on multiple sources and present it using 8-10 slides which took about a week's worth of work. Of the four people on the call, only one seemed engaged and the others seemed to be working on secondary screens. A few days later I received an automated rejection email. The recruiter who had recruited me via LinkedIn didn't even personalize it or send a note. I would never consider working for this company as a result. They are supposed to be an industry leader on work and work experience and this is how they conduct their hiring process and treat candidates?