Canada

It was a strategy that made a half-assed amount of sense during the years where the Liberals were struggling. Canadians (particularly Ontario) seems to like their politics roughly center. So if you want to supplant the Liberals as the main party representing the Left, you can't be too far left. Same thing happens to the Conservatives. Every time they drift too far right to appease the Alberta crowd, they start losing the Ontario suburbs.

Plus, "socialism" is still a bad word for most of the older population. You can get rid of the word, change none of the policies, and that will be enough to keep the "socialism bad" crowd happy.