This cuts both ways. You have conservatives who used to work for the government and spoke out against the government when it was headed by Biden. Trump himself, while out of office, often spoke publicly against the Biden foreign policy and said what he'd do differently. If you use the Logan Act to criminalize what former Democratic officials do, the same thing will happen to Republicans. And none of those Republicans were charged with Logan Act violations by Biden because they knew the problem with it.
Second, you mentioned classified information, and IF someone with access to classified information discloses it, that is a separate crime that can be charged. The Logan Act has nothing to do with it.
“The government” is not always following the Constitution, which was the case with many of the Biden initiatives. So one cannot overgeneralize or assume moral equivalence about how either party criticizes “the government.”
The entire thrust of the Democrat Party is to “lberalize”, to color outside the lines, to make “progress” that they only define in terms of moving the society away from bedrock values and forcing people to transgress deeply held convictions that should be established by the voters, such as when 30 states defined marriage as being between a man and a woman, yet lib/prog judges overturned these measures in state after state. Just as lib/prog judges are pushing the envelope against Trump’s determination to set us back on our Constitutional foundations.