It is a well documented strategy for left-leaning politicians to import voters through unchecked immigration in an attempt to create an unassailable electoral base.
In this case, the politicians who "sow hatred, insecurity, fear and division for their own ends and don't care what mess they leave behind," are the leftists.
See the rapid, shocking, galling decline of civil society in some western European countries in recent years.
These mass immigration leftists sow hatred and insecurity when they act as if the natives of the western world(genetic Europeans,) are somehow in debt to the rest of the world for past sins. Strangely overlooking the fact that the entire modern world with all its convenience and affordances, huge improvements in health and nutrition etc. etc., are more or less entirely the product of Europeans. All peoples can look at some past actions with regret, but Europeans have clearly been a net positive on the world at an unprecedented scale.
These mass immigration leftists sow fear and division when they support the importation of huge population groups with the bonkers notion that these groups will then start behaving along the societal norms of the country they've been imported to, rather than the country they came from.
So the Trumpers are right, their country is being taken from them in this way.
But before we get too far in the weeds on a patented HN thread of only the most tenuous relevance, Congratulations Bob!