You did not ask a question as usual - you posted a click bait headline to a political story you wanted to promote. But you did open a thread to debate use of capital gains for growth on investments vs. income and the majority of people have taken time to explain it to you. But you don't want to hear arguments that don't support your political agenda.
Do you support the idea of a multi-millionaire who can afford to donate £1.5M to a political party and his wealthy mate asking the public to donate money to a legal challenge which will likely have no legs? Are you familiar with the tax efficient schemes that this person has himself used? Perhaps you'd be interested in researching these, before championing his cause.
How can you argue we have a tax system "designed to treat the rich more generously than ordinary working people." When these people pay the vast majority of all taxes and these rules are open to all.
There is no income threshold for declaring capital gains - open to all.
Ordinary working people who buy, renovate and sell property can benefit.
Ordinary working people who invest in a few stocks can benefit.
Perhaps you need a tax advisor?