Like all of us, aphids are hungry and show up earlier in the season than the other beneficial insects that come later and help to keep them under control. Fun fact: Aphids can actually give birth to daughters who are already pregnant with the next generation so their numbers can increase quickly.
The false sunflower is a native plant and the red aphids are a native species as well so they have evolved together in harmony with each other and other native species- birds, insects, wildlife etc over eons long before we were here, so it's all natural and not really of concern.
The less pesticides people use in the yards and the more good habitat that is there makes it easier and more likely for beneficial insects/birds etc. to help with pest control.
You don't need any pesticides though- you can put on gloves and squish some of them or wash them off with the hose.

Here are some of the 'good guys' that help out in the garden: 
https://extension.umd.edu/resource/predators/


Christine