There’s too much of the culture of entitlement shining through some of these responses.
BA isn’t a charity.
Its Lounge Offering is a key differentiating factor between Economy and Premium Cabins.
If you want additional guests, beyond the already generous allowance of one accompanying guest, you need to book into a cabin which allows lounge access, or ensure you have sufficient elite status oneworld members in your party to “sponsor” your guests.
If it’s not possible for you to do that, upgrade using miles, join the Priority Pass lounge scheme (where available) or simply set up camp in a restaurant within the terminal complex.
Honestly, not that complicated.