My theory for this is that such people (relatives of mine included, sadly) are just higher on Maslow's heirarchy of needs. At the bottom you need roti-kapda-makaan (food, clothing, shelter), followed by bijli-sadak-paani (electricity, roads, water) and higher up health and education. If you've had all of this all your life, you take them for granted. When Modi comes along and peddles a grand vision to Make India Great Again, like it was in Vedic times, that captures the imagination and inspires us. When the BJP tells us that all of our problems are because of Muslims and that we need to put them in their place to fix everything, we're only too willing to listen.