Deereyme get you facts right, people are not booing the players they are booing what blm stands for. Maybe you should look at their website to see what kind of organisation they really are.
BLM are not one single group. It’s more of a broad church spanning many people from varying backgrounds. Some will do it solely to make a stand against racism, others will be more Marxist inclined. However, the latter do not represent the full, since it’s not run from one grouping as such. Many go just to make a stand against racism without wanting to push a more socialist agenda. Heck, the knee taking predates the movement, so it can be separated from that if needed.
I think it’s safe to say that footballers fall into the category of those wanting to take a stand against racism without pushing any kind of political agenda, so booing for this seems misjudged, especially given they have explicitly said they are doing it for opposition to racism. This would make it seem to them they are being booed for anti-racist gestures, since they have explained it’s not a support of politics.
Personally I am unsure as to whether it’s having an effect now; it’s been happening for a while and little seems to have been achieved. However, booing just seems mean spirited when they have made it clear it’s to highlight the issue of racism.