Borrowing is nearly always voluntary. Somebody might want to lend to me, but they can't force me to borrow from them if I don't want to. But there's an exception. A country that issues the reserve currency can be forced to borrow from other countries, if those other countries want to lend to it. This point helps us understand the relation between China and the US.
To understand this point, lets go back to the gold standard first. Suppose gold is the only form of international reserves. Suppose one country, let's call it "China", decides it wants to hold a bigger stock of gold reserves. If the world stock of gold reserves is fixed, the only way that China can hold more gold reserves is if other countries hold less gold reserves.
What happens if China wants to hold more gold reserves, but all other countries don't want to hold any less? The result is world deflation, as each country raises interest rates to either acquire more gold reserves or prevent an outflow of gold reserves to other countries.
Eventually this deflation will provide the solution. Deflation can't increase the tonnes of gold reserves in existence (except very slowly, by encouraging more mining), but it will increase the real value of that fixed stock of gold reserves. Each tonne of gold will be worth more in terms of other goods, and countries care about the total value of the tonnes of gold they hold, not about how many tonnes they hold. So deflation ensures that the real value of the world stock of gold reserves will adjust to equal the sum of the real values of gold reserves demanded by all the countries.
But world deflation is not a very pleasant solution to the problem of an increased world demand for international reserves. So the gold standard isn't a very good system.
Now suppose that the US dollar replaces gold as the international reserve currency. And again suppose one country, call it "China", wants to increase its real stock of reserves.
There are two differences between dollars and gold as the international reserve. First, the US can print more dollars at will; it can't print gold. Second, dollars are a liability of the US; gold isn't.
To avoid deflation, the US can increase the stock of international reserves by printing more dollars. Or, it can hold the stock of dollars fixed, and allow deflation to increase the real value of the existing stock of dollars. But either way, the real value of US liabilities to China would increase. The US is forced either to print more dollars to lend to China to avoid deflation, which directly increases the real value of US liabilities to China; or else the US must accept the deflationary consequences of not lending to China, which nevertheless still increases real US liabilities to China by the same amount. Either way, the US is forced to increase the real value of its liabilities to China if China wants to hold an increased value of international reserves.
"Blame China" is not necessarily the lesson to be drawn here. It is quite understandable that some countries might legitimately want or need to accumulate international reserves. "Blame the international reserve system" seems a more appropriate lesson.
For example, if China allowed the US to accumulate yuan, the US Fed could hold yuan reserves, just as China holds dollar reserves. Then, if China wanted to increase its dollar reserves but the US didn't want to increase its liabilities to China, then China could accumulate dollars, and the US Fed could accumulate an equal value of yuan.
Perhaps, if we want to blame China for something, we should not blame it for buying dollars. We should blame it for not allowing the US to buy yuan.