There's a travel ban on Bolsonaro for a reason — and allowing him to travel to attend the Trump's inauguration ceremony would put his own private interest ahead of the public's. Bolsonaro is a coup plotter who has long advocated for Jan. 8, 2023, rioters to flee the country to avoid prosecution, so it's very likely that he would not return to Brazil as well.
This is the latest politically-motivated judicial decision against Bolsonaro as the country's top court colludes with the leftist government in an abhorrent lawfare targeting the opposition. If Bolsonaro were to flee Brazil and claim political asylum, he would have done that after he attended the inauguration of Argentina's Javier Milei in December 2023.