Most people do not practice altruism and would not dream of feeding the next door neighbour's children instead of their own but they feel guilty for not practicing what is taught as a noble thing so they vote for the party that proffers altruistic programmes -especially if they are wealthy where their guilt is magnified proportionately.They get politicians to do on their behalf what they are unable to practice in their own lives. Altruism by proxy is the result.
Where does the guilt come from but the residual Christianity upon which the West has been indoctrinated for centuries. The outward forms of religion have long been abandoned but the essential altruistic preachments of the gospels remain imbedded in the culture and manifests in politics.
People will accept a little bit of altruism in their politics but not in an unadulterated form as with Corbyn which is why he is unlikely to become prime minister although note that people are still sympathetic to his 'ideals' but dismiss them as 'impractical' and vote instead for the diluted Altruism Lite of Theresa May. But the fact remains that she has to include elements of altruism in her manifesto if she is not to appear heartless and endorsing selfishness which is testimony to the continued and enduring influence of altruism and all politicians know they must invoke it to some degree in order to stand any hope of gaining power.
Until a morality of selfishness is invoked and a critique of altruism from a moral ethical perspective a la Ayn Rand is articulated altruism will continue to have a vice like grip on the culture and polity and people will continue to vote into office politicians who advocate suicidal collectivist statist altruistic socialsitic programmes that impoversih the country and erode the liberty and freedom of the people in an inevitable and ultimately invidious authoritarian direction.
The idea that the battle for ideas can be won on the field of economics is deluded and ahistorical. The people of Venezuela are dying of starvation,there are no dogs or cats on the street,they have all been eaten,there are no animals in the zoos,ditto but the people are still wedded to socialism as an ideal, all the economic logic to the contrary. It is ideas that move nations not economics and the conservative right made a terrible error when they chose economics to fight socialism rather than morality ceding the latter to the left with disastrous consequences. Without a vocabulary to challenge the faux morality of the left conservatism will continue to cede ground,appropriate socialist programmes (see Theresa May's Manifesto) and thus pave the way for ultimate victory by the collectivists.