If a person living in the UK has 5 children it is expected that this will be paid for on the NHS. If she needed IVF to concieve those 5 children then some of this help will be paid for on the NHS and this will not make it into the Sun, regardless of whether that person has ever paid a penny into the NHS or not.
The Sun is focusing on ONE case of ONE person - they are not presenting a balanced report on health tourism. They are picking a "sensational" example of health tourism knowing that it will cause outrage amongst its readers. Perhaps it is just a co-incidence that the health tourism anecdote they have selected focuses on a black, african woman who now "needs to stay in this country and have her 5 black children supported when white kids can't even afford..whatever".
You know and the Sun know that will be the reaction from a large proportion of its readers You are entirely correct that it would "be good to know the stats on helath tourism", but then the Sun doesnt bother to report those does it?