I think they granted you the exemption because you (politely) persisted to the point where they just let you go rather than deal with it. If you read the Order, normal business travel most definitely does not qualify as essential. Essential means to provide (or will provide upon entry) an essential service such as a health care worker, flight crew etc, not to feed your family. The service must be essential enough to Canada (not essential to you) to warrant taking the risk of not making you quarantine, not just because you need to go on a business trip. And I think we all know that.

https://orders-in-council.canada.ca/...=39482&lang=en

Exception — requirement to quarantine

6 The requirements referred to in paragraph 3(1)(a) and subsection 4(2) do not apply to

(a) a crew member as defined in subsection 101.01(1) of the Canadian Aviation Regulations or a person who enters Canada only to become such a crew member;

(b) a member of a crew as defined in subsection 3(1) of the Immigration and Refugee Protection Regulations or a person who enters Canada only to become such a crew member;

(c) a person who enters Canada at the invitation of the Minister of Health for the purpose of assisting in the COVID-19 response;

(d) a member of the Canadian Forces or a visiting force as defined in section 2 of the Visiting Forces Act;

(e) a person or any person in a class of persons whom the Chief Public Health Officer determines will provide an essential service;

(f) a person or any person in a class of persons whose presence in Canada is determined by the Minister of Foreign Affairs, the Minister of Citizenship and Immigration or the Minister of Public Safety and Emergency Preparedness to be in the national interest, as long as the person complies with any conditions imposed on them by the relevant Minister to minimize the risk of introduction or spread of COVID-19;

(g) a person permitted to work in Canada as a provider of emergency services under paragraph 186(t) of the Immigration and Refugee Protection Regulations;

(h) a person who enters Canada for the purpose of providing medical care, transporting essential medical equipment, supplies or means of treatment, or delivering, maintaining or repairing medically-necessary equipment or devices, as long as they do not directly care for persons 65 years of age or older within the 14-day period that begins on the day on which the person enters Canada;

(i) a person who enters Canada for the purpose of receiving essential medical services or treatments, other than services or treatments related to COVID-19;

(j) a person permitted to work in Canada as a student in a health field under paragraph 186(p) of the Immigration and Refugee Protection Regulations, as long as they do not directly care for persons 65 years of age or older within the 14-day period that begins on the day on which the person enters Canada;

(k) a licensed health care professional with proof of employment in Canada, as long as they do not directly care for persons 65 years of age or older within the 14-day period that begins on the day on which the licensed professional enters Canada;

(l) a person, including a captain, deckhand, observer, inspector, scientist and any other person supporting commercial or research fishing-related activities, who enters Canada aboard a Canadian fishing vessel or a foreign fishing vessel as defined in subsection 2(1) of the Coastal Fisheries Protection Act, for the purpose of carrying out fishing or fishing-related activities, including offloading of fish, repairs, provisioning the vessel and exchange of crew;