at the end of the day 'Saints RL' or 'St Helens RLFC' is a business, its management needs to do whatever they feel is the best thing to ensure its long term survival.
The new ground is in St Helens, the only change is that the initial impact that new sponsors/fans will get is of the 'Saints RL' brand.
As a quick straw poll, look at all the usernames on here - how many people actually have the full club name in it, and how many have the word Saints.