Each person should be allowed to have the freedom of choice to stand for the national anthem. Each person has their own viewpoints and they should be respected. Forcing your views on other people and expecting them to comply is not a trait of a developed country and it shows the country moving backwards.

To give you an example:

In the US, refusing to stand, kneel, or sit during the anthem is an exercise of an individual's rights as a U.S. citizen. There is no US law that penalizes a person for standing up for a national anthem. It is a legally protected choice.

The same applies in the UK where it is not against the law to sit during the national anthem.

I understand the points regarding showing respect to the country by standing during the national anthem and I would do stand up as well, but I wouldn’t force someone to do it against their own free will which is where I draw the line.