the fact is, they've chosen to make their protest known by using a gesture that - to a large number of people - implies support for a controversial movement that many people (including btw myself) do not support
Okay, the players have explained several times why they are taking the knee, Southgate wrote a rather eloquent letter explaining why they are taking the knee, the reaction of some pondlife after the tournament will no doubt strengthen their resolve to keep taking the knee - and they've all repeatedly explained that this is a respectful gesture and nothing to do with Gramsci/ Marx/ public ownership of the means of production... but other people still claim that they are supporting and endorsing all of the "controversial" things that you claim...
...so, since I can't convince you that they are using a long established gesture (that people were doing decades before some edge lord activists tried to claim it as their own), let's look at it another way...
...whilst the (far) left keep trying to seek traitors and demonise those who only agree with 95% of the same things as them, the (far) right have a much cleverer approach, of trying to assimilate popular things as evidence that people support them.
So, we have the likes of Britain First co-opting the (British Legion's) Poppy and trying to make that a touchstone for their own campaigns... in the US there's the Trump-supporting "Proud Boys" who dress in Fred Perry/ New Balance and claim that as their "uniform", so that anyone who wears Fred Perry/ New Balance is one of theirs and subscribes to their beliefs (even though large numbers of people were wearing those brands for many years before, and many of other people aspired to those brands regardless of politics). They do the same about the "okay" gesture (where you form a circle of thumb and finger, with the other fingers pointing up).
I'm probably the kind of milquetoast beta-male person that the Proud Boys would hate, but I continue to wear New Balance (have been to the Factory in Flimby a couple of times, great to have manufacturing in the UK rather than buying imported shoes from other companies) - I've bought the occasional Fred Perry top in local charity shops - they both seem good quality brands that are a cut above the "norm" (so it's a clever move, because it conflates "brands that people like" with "supporting the Proud Boys").
Now, if I see someone wearing both of those, I don't automatically think they are Proud Boys supporters, even though that's the "uniform" of such people - I don't assume that they are implying support for a controversial movement (just like I don't think that someone wearing a Poppy is a Britain First fan)
The world is full of campaigns where opponents can find a rogue 1% on the opposite side and paint that as somehow representing everyone - e.g.many people will have nuanced views of Israel/ Palestine, but it's easy for someone to find one example of activists on one side (who sent a tweet saying how much they wanting to "crush" the other side) and suggest that they represent everyone.
There are a number of causes I could get behind where (some of) the activists who generate the most noise are deliberately provocative/ antagonistic/ more focussed on annoying opponents to keep the hardcore energised than actually winning support from "neutrals" - look how the likes of PETA behave
I don't assume that the England players support every war that the British Empire carried out just because they sing a song praising the Monarch at the start of each match - I don't assume that the England players support all religious wars just because they sing a song praising God at the start of each match - I don't assume that the England players are warmongers just because they wear poppies during matches in October/ November - but a lot of people seem happy to conflate kneeling with the entire agenda of some radical Americans.
But, if people don't listen to the players/ manager repeatedly explaining that "kneeling" =/= "backing Marxism" then I guess there's nothing I can say that'll change their minds either
At the point at which the Spectator is arguing that the Tories have made a mistake with their approach to this taking the knee issue is it perhaps time to accept that it isn't the England football team that are the problem here?
It's funny - they've "won" lots of culture war stuff, but seem to be coming unstuck on a number of things like face masks and taking the knee... quick, whip up a store about Gypsies or pretend that "Brussels wants to ban our sausages"!
Starmer appears to have started his summer campaign, planned in the wake of the local election results to try and understand party issues in the eyes of former voters and come up with related policies, with a visit to a hustings in Blackpool yesterday:
He's making the right sounds here - it's a bit "hair shirt" but he's showing that he understands that Labour lost and wants to learn why Labour lost - whereas Corbyn arrogantly kept on with the same approach after his 2019 defeat
I think that a number on the Canary/Novara wing of the party are unhappy with the idea of listening to the people that didn't vote for Labour since Blair stood down
But you need to listen to the people who stopped voting Labour to find out what you need to do to try to win them back