As far as I'm aware, China has been giving loans to various countries in Africa and building infrastructure in exchange for money and maybe some stuff like recognizing Taiwan as part of China. But why do people say China is imperialist for doing this? Is there truth to it or is it another strain of radlibs eating state department propaganda?
Depends on what you mean by "influence".
Being a person that can be relied on by others to help them, increases your influence with those people you help. Proving yourself a valuable friend can increase your influence among the people you hang out with.
You can gain influence both through subterfuge/coercion or just by being a decent creature.
The USA could increase its influence by trying to have a good reputations with other nations, but usually can't keep the need for dick swinging in check long enough to do so. Sure, the PRC could have some nefarious scheme going on... or it could just being trying to work with other countries that could use the help.
My personal view is that they see an opportunity and went for it.