For anyone saying things like, "if you are a business, you can decide who you provide service to", i.e. "its acceptable to refuse to video a same-sex wedding, because, private business". That's not how the Ontario Human Rights Code works. https://www.cbc.ca/news/canada/london/same-sex-couple-brides-denied-service-1.5657191
Here is section 1 of the Code. It's pretty clear. When it comes to service, you can expect to be treated equally and without discrimination based on a protected ground.
In simple terms, if you are a special interest organization, you may be allowed to limit "membership and participation". If you are registered as someone who can solemnize a marriage, you may also be allowed to refuse to solemnize a marriage based on your religious beliefs.
So, e.g. if you are a private Christian club, you can deny someone entry into your club based on their religion. But there are three things you have to show in order to qualify as a special interest organization (screen capture from http://www.ohrc.on.ca/en/policy-preventing-discrimination-based-creed/8-defences-and-exceptions)
If you are also part of an organization that favour certain groups in order to ameliorate their situation to address historical disadvantage, you may also fit within an exception:
But here's what it comes down to: if you think "private businesses" can do what they want, it has been many many years since that's actually been the case. (sidebar: read this fascinating historical case from 1906: https://www.thestar.com/news/gta/2020/02/16/his-family-was-banned-from-a-toronto-roller-skating-club-for-being-black-he-fought-back-in-court.html)
If private businesses could do whatever they wanted, you could be legally denied a coffee because of your skin colour. You could be legally turned away from a retail store because of your gender. You could be legally told that you won't get internet because of your religion.
I think we can agree that most of us don't walk into a major supermarket and, if turned away due to our religion or sexual orientation or ethnicity, think "ah well, its a private business, so that's ok". But for some reason, in this case, it seems to be a prevailing theme.
Add before you quote the Charter and freedom of religion at me, Charter does not apply to private businesses. And on a similar vein, before you ask me, "what about my right to my religious beliefs?" - no one says you do not have a right to hold whatever beliefs you want. But..
That doesn't necessarily mean your beliefs allow you to act in a way that discriminates against others. Tl;dr? Don't discriminate against someone based on sexual orientation or any other protected ground.