I appreciate the concern over this issue. Individuals must fulfil a range of criteria before being granted entry to, or leave to remain in, the UK. As there are multiple kinds of visa, these criteria can differ, but common requirements include the ability to support oneself, a good knowledge of the English language and the absence of particular criminal convictions.
 
All applications are assessed on a case by case basis, according to their individual merits and against the part of the Immigration Rules which relates to the purpose for which they are seeking entry. 

I believe it is fair to have rules on bringing spouses from abroad into this country and on family reunion. Indeed, The Supreme Court has upheld the lawfulness of the minimum income requirement for spouse visas, which prevents burdens on the taxpayer and promotes integration. The Supreme Court agreed that it strikes a fair balance between the interests of those wishing to sponsor a spouse to settle in the UK and of the community in general. However, the Home Secretary has been clear that the Home Office constantly reviews the rules to ensure they continue to be fair.