Most of my work has been for smaller organisations in highly competitive environments. In these organisations HR is not an empowered function and most hiring is done personally by managers. In larger organisations and those that are not subject to much competition for example, the BBC or Microsoft, then HR and their hiring quotas and practices are very important.
The reasons for this are illuminated by the this interesting academic study of the performance of Royal Navy captains during the Age of Sail.
Imagine going to work for your uncle at an early age. Then, after a few years, you pass a major exam in front of a panel chaired…by your uncle, who has in the meantime risen to a position of major influence. Before long, at the tender age of 21, you find yourself in charge of 200 men, making life-and-death decisions on your own. What are the chances that an organisation where such a career path is not just possible, but common, will do very well?…
https://voxeu.org/article/patronage-and-performance-age-sail
Conclusion
Senior managers with personal knowledge of candidates are well-placed to pick winners. In highly competitive environments they will strive to choose the best candidate for the organisation. In non-competitive environments they may indulge their own preferences.
Therefore the solution to discrimination is not hiring quotas to make sure that everyone feeds equally from the corporate trough but greater competition.
This provides a strong theoretical justification for exempting small businesses from HR compliance burdens.
Dr James Bayley 
Your writing is extremely difficult to read because of your many errors. You frequently leave out words, such as “of” and “from,” making your writing more difficult to decode. You misuse “logon” which is a bad condensation of the verb “log” and “on” (sometimes in/off/out rather than on). The condensed version had become a noun, but you now use it as a verb–error upon inherited error. In my linguistics class, we learned how languages change the fastest when education is of lower quality. You’re a doctor of some kind? You’re joking.
Let’s forget linguistic studies and keep things at grammar school level. Check your mechanics and punctuation. Most recently, your post on whether managers or HR should do hiring contains errors that were not allowed past sixth grade. Not only did you forget to capitalize Age of Sail properly, given that it’s a proper noun that names an era, but you also used the wrong homophone–sale instead of Sail. That error was made while referring to an article that DID give the correct name. Then, when creating the link, you left off the last letter of the link. It’s as if you don’t care about your reader, but are simply splattering out posts just for the ad revenue (if your site has ads). These errors are the kind made by someone really lazy and typing on a phone while not truly caring. They make your material more difficult to read because of all the decoding imposed on the reader.
Thank you for the feedback Mike. I have made the corrections that you have suggested. I think that we will have to agree to disagree about ‘logon’ although I can see it is an issue that you feel strongly about. Thank you for pointing out the ads. I use “wordpress.com” and they don’t show me the ads – I didn’t even know they were there. I will have to move to a paid host.