I mean, the thing is, for those folks that say "but all lives matter!" - yes, of course they do, but until ALL lives actually matter, until BIPOC lives are shown to matter and have as much worth and equality as white lives; the phrase "all lives matter" is a smokescreen for people that may have a more, hm how to say this... unkind mindset to hide behind.
The BLM movement isn't problematic in and of itself, not at all.
Until people start listening and stop killing BIPOC, until equality is an actual thing and lives aren't being lost in this senseless, violent and meaningless fashion then no, I personally do not believe that the BLM movement is problematic.