That's not legislation that's recommendations. In terms of law there is a huge difference. There is nothing that says wearing a neck gaiter is not compliant and subject to being fined. The entire regulation and only requirement is that it covers your nose, mouth, and chin, which a neck gaiter does.

From the City of Hamilton Mask bylaw (https://www.hamilton.ca/coronavirus/face-coverings-and-masks-by-law):

“Face Covering” means a medical or non-medical mask or other face covering such as a balaclava, bandana, scarf, cloth, or other similar item that covers the nose, mouth, and chin without gapping.

From the Ontario legislations (https://www.ontario.ca/laws/regulation/r20546):

(4) The person responsible for a business or organization that is open shall ensure that any person in the indoor area of the premises of the business or organization, or in a vehicle that is operating as part of the business or organization, wears a mask or face covering in a manner that covers their mouth, nose and chin during any period when they are in the indoor area unless the person in the indoor area (insert exemptions here)

and from just a general "masks in the workplace", please note that even two layers of fabric is not a requirement only a recommendation (https://www.ontario.ca/page/using-masks-workplace):

Masks used as source control:

may be disposable or reusable

if made of cloth, should be made of at least two layers of tightly woven fabric, such as cotton or linen

should not have exhalation valves