Although feeding stray cats can feel like a kind gesture to do, it can actually do the opposite of helping; in fact, it may be more damaging in general. Feeding these stray cats causes the stray and feral population to actually increase by giving them food, increasing their livelihood, which in itself is a good thing except for the fact that these cats are able to reproduce, and that is where the main issue lies.
Their reproducing is causing more stray cats, which can cause the cat population to skyrocket compared to other animals in the wild. Their species then becomes an invasive species since they are killing birds, squirrels, rats, etc. before they have enough time to reproduce, causing their own numbers to decrease rapidly. For example, the rapid number of stray cats has caused 63 species to go globally extinct, and an estimated 1.3 to 4 billion birds are killed annually. And although these animals that we as a society give no attention to are quite important to keep the cycle of the ecosystem going.
To give you an example of how important these animals are, birds play an important role in reforestation through seed dispersal. Oftentimes birds, like the blue jay, dig their seeds to save them for later, but birds being birds aren't able to find all of the seeds they once buried, and that leads to those seeds sprouting into trees or bushes. And that's just one of the reasons that birds are so important.
So we as a society should do our best to not only care for our cuddly friends but also our feathered friends, furry friends, and our scaly friends. If you still want to help a stray cat, you should instead provide a safe shelter, look for any chips (maybe someone's lost cat), or support TNR, which stands for Trap, Neuter, and Return, to prevent the population from growing. Because at the end of the day, you cannot feed every cat in the world, but you can help the ecosystem by not placing that plate of food.