Romney said the following, regarding Trump:
"When the only American citizen President Trump singles out for China’s investigation is his political opponent in the midst of the Democratic nomination process, it strains credulity to suggest that it is anything other than politically motivated," Romney tweeted.
But he misinterprets Trump's reason for citing Biden, which is to show that the anti-Trump movement is biased, otherwise they would just as easily make a big deal out of Biden's involvement in China.
Romney is confounding things by saying Trump is biased against Biden. He is implying that Trump is accusing Biden as something other than an example to illustrate how biased the anti-Trumpers are in their calls for impeachment.