The government doesn't care about Londoners. Partly because inner (but not outer) London votes Labour, but mainly because for a long time - several decades - money is made in London, often at the expense of Londoners. This is no exception.
Tbh though the football crowds won't make a huge difference. London has had 100s of 1000s of international travellers arriving weekly throughout the pandemic - with most heading straight from the airport onto packed public transport...
It's strange really. If it's safe to have football and then tennis crowds (and the airport travellers) in London. Yet it's not safe for MPs to return full-time to Parliament...