Tornado bird tornado cannot be outrun at base move speed

You have pushed back on the idea of making move speed innate on boots (obvious no brainer, should happen). If you think that stat should be optional, why is a guaranteed death mechanic on a boss unavoidable without it? I have 8k total health and hp. Tornado burned through that twice (omen proc'd) plus whatever health I chugged. Tell me how move speed is optional.