Their argument largely hinges upon the export of capital/loans; however, economists have already shown that the People's Republic of China has always been an active international lender even in the 50s, 60s, and 70s under Mao.

The Soviet Union under Stalin also played a critical role in developing China with massive loans to build its infrastructure and the industrial foundation that was key to China's economic independence. These Soviet loans were certainly not an altruistic giveaway and had to be paid back. According to Deng Xiaoping:

Stalin, on the other hand, did some good for us. After the founding of the People’s Republic, he helped us to build up an industrial complex that is still the foundation of the Chinese economy. He didn’t help us for free — fine, we had to pay him — but he helped us.

Numerous Marxist economists and scholars including Michael Roberts, David Kotz, Junshang Liang, Zhonglin Li, Lijun Su, Guglielmo Carchedi, and Minqi Li have shown that China is not an imperialist country in a Marxist sense. China's focus on mutually beneficial state-led projects for direly needed infrastructure, industrialization, schools, hospitals, manufacturing, and power generation are all critical developments required by the global south to break out of their state of underdevelopment and dependency inflicted upon them by the western imperial core. China's international loans and trade deals do not impose neoliberal structural adjustment programs of privatization and austerity or other harsh conditionality measures that are utilized by western capitalist countries and western-dominated financial institutions like the IMF.

According to Marxist economists David Kotz and Zhongjin Li:

More importantly, Horn et al (2019) also find that unlike other major economies, almost all of China’s external lending and portfolio investment is undertaken by the Chinese government, state-owned companies, or the state-controlled central bank, not by private investors that follow the logic behind profit-oriented decisions.

Chinese official lending programs, such as the more recent Belt and Road Initiative (BRI), function as a vehicle for China’s economic statecraft and international cooperation, rather than a search for state domination. Moreover, the investment and loan decisions are mainly channeled through two policy banks, the Chinese Development Bank (CDB) and the Export-Import Bank of China (Chexim), which are largely development-oriented and policy-oriented financial agencies still controlled by the state that aim to achieve the policy objectives of the party and state, rather than originating from private capitalists in pursuit of profit.

By investing and lending largely to developing countries, especially low-income countries, and promoting industrialization in the global South, China is seen as supporting initiatives to address development problems not solved by neoliberalism’s corporate initiatives. While China’s current approach is more commercial than formerly, it continues to support state-run projects in industry and agriculture, which contrasts with the insistence in Washington Consensus on the conditionalities of structural adjustment programs (Sautman and Yan, 2007).

The evidence suggests that China’s strategic lending programs are aimed at reaching mutually beneficial deals rather than at securing conditions for extracting extra-high profits by Chinese capitalists abroad.

Chinese capitalists have treated local workers similarly to the treatment by capitalist investors from other countries, while by contrast Chinese SOEs have been more responsive to requests from the host government regarding more job creation and better labor conditions (Oya & Schaefer, 2019).

Other research also has found that Chinese projects create net employment for national workers and crowd in domestic firms as well.

A new Monthly Review article by two Marxist economists on more recent developments in imperialism: https://monthlyreview.org/2021/05/01/five-characteristics-of-neoimperialism/