As a medical professional, and a famous one whose opinions many people will take as verbatim, it is disgraceful to basically spread lies about an important topic. Not only is he totally factually incorrect, he stated that he's quoting the NHS guidelines, which is not true, as they support longer BFing.
OP, this is not an issue where there's a clash of opinions or studies with wildly varying results. Every single study on breastfeeding and breastmilk delivers the same results, every time; that it is the optimal nutrition for babies, that the longer they are BFed the better, that longer-term BFing simply does not psychologicaly damage children, that BFing, esp. for longer, ultimately makes children more independent, and so on. These are the facts; anyone, including Dr Christian ShitHair, who claims differently, is either woefully misinformed and shouldn't be trying to pass themselves off as knowing about the subject, or they have their own weird, negative agenda.
BM also continues to change as the child grows and ages, to deliver what the child needs at each stage. No other foodstuff on Earth does that. The nutrients in milk from other creatures, and formula, will always be the same. BM is like tailored nutrition. The longer a mother BFs for, the more health benefits she garners for herself, also (lowered chance of certain cancers, etc.).
And for the poster who asked who on earth would want to Bf a child until they were 8, the answer is: Mongolians. BFing up to 10 isn't unknown, and they claim that their menfolk are the toughest on Earth precisely because they breastfeed for so long as children. Genghis Khan was said to have BFed until he was 8; I've heard he was fairly tough and independent.
As with all comments about BFing, I hasten to add that none of what I write implies any criticism of not breastfeeding, through choice or circumstance.