Haven’t deaths of police officers skyrocketed since BLM? Your chart only goes to 2014.
Here’s the website for “Officer Down Memorial Page,” if you’d like to crunch some numbers. If you could isolate deaths-by-violence for 2014-2018 and compare to the numbers for 2009-2013, that might show an effect.
(I’m not sure whether those are accurate dates for the BLM movements, but I’m sure you get the gist of it.)
Apparently not:
https://www.usatoday.com/story/news/2017/12/28/number-officers-killed-2017-hits-nearly-50-year-low/984477001/