Copy assignment is disabled for thread in C++11

void exec_produce(int duration) {
    //阻止线程运行到duration秒
    this_thread::sleep_for(chrono::seconds(duration));
    //this_thread::get_id()获取当前线程id
    cout << "exec_produce thread " << this_thread::get_id()
    << " has sleeped " << duration << " seconds" << endl;
}

int main(int argc, const char *argv[])
{
    thread threads[5];
    cout << "create 5 threads ..." << endl;
    for (int i = 0; i < 5; i++) {
        threads[i] = thread(exec_produce, i + 1);
    }
    cout << "finished creating 5 threads, and waiting for joining" << endl;
    //下面代码会报错,原因就是copy操作不可用，相当于是delete操作，所以报错
    /*for(auto it : threads) {
       it.join();
    }*/
    for (auto& it: threads) {
        it.join();
    }
    cout << "Finished!!!" << endl;
    system("pause");
    return 0;
 }

I want to know why the code threads[i] = thread(exec_produce, i + 1); is correct? Is it not use the copy function? I see the rule as follows:

1) move Assignment operation: thread& operator= (thread&& rhs) noexcept, if the current object is not joinable, you need to pass a right value reference (rhs) to the move assignment operation; if the current object can be joinable, then terminate () error.

2) Copy assignment is disabled: thread& operator= (const thread&) = delete, thread object cannot be copied.