Adapt to the new environment or die. CHC is just the first of the major operators to try this (if it's true). Many other operators have been operating without unionised crew for years.
In an environment where contracts are being lost, often by only a handful of thousands of $/EUR/ GBP a month, it is hardly surprising that any operator would not be looking for ways to reduce their crew costs which more often than not are the biggest expense when bidding a contract.