Whatever you think about it, they do have that right. Most people who currently arrive in small boats have their claims recognised as legitimate under UK law. This also means that your characterisation of them as having economic or sinister intentions is a lie.
They’re not safe in France because France’s asylum system is also in very poor shape. They are mostly people living in temporary camps, unable to find work and relying on charity. This is not the same thing at all, obviously, as most French people living in France, and is not safe for them. Furthermore, there is no compulsion for refugees to stay in the first ‘safe’ country they reach, although in fact most do.
Even if everything I said above was false (which it isn’t), the British government could afford to fix the problem far more cheaply by investing in processing the claims more quickly. Processing asylum claims quickly would remove the incentive to pay people smugglers and thus break their business model. Instead, the government is spending huge sums of money - more than would be required to process those claims - on this policy. Even if it does work, it will be more expensive than just processing the claims, quickly.