Flynn Jr is spreading tweets from Brittany Pettibone, David Seaman and other spreaders of pizzagate disinfo such as Joe Biggs (Infowars reporter who spread We, The pizza hack disinfo)

Flynn Jr is not simply a pizzagate supporter who is unaware that these people are disinfo shills. He was paid by his father's lobbying firm "Flynn Intel Group Inc". He is plugged into what is going on and is not doing any of this by accident.

Flynn Jr was also fired by the Trump campaign due to the controversy due to his pizzagate tweets. Hit pieces were written that falsely accused the administration of requesting a security clearance for Flynn Jr:

Before they fired Michael Flynn Jr. over Pizzagate conspiracy theory, Donald Trump’s transition team wanted to give him security clearance

The claim that a security clearance was being requested for Flynn Jr was refuted by the Trump administration: Pence aide denies security clearance was requested for Flynn Jr.

The elder Flynn has also been intentionally making problems for Trump:

Recently, there were new hit pieces on Michael T Flynn recently for his firm doing lobbying for a Turkey firm just prior to the new administration taking office: Turkish client paid $530,000 to Michael Flynn's consulting firm (Flynn Jr was also paid for this lobbying)

Of course, previously Flynn has been criticized for misleading vice president, others about a phone call with the Russian ambassador

Michael T Flynn likely concealed his Turkey lobbying work from The Trump administration: White House: Trump unaware of Flynn's foreign agent work

Conclusion

The Flynns were (and still are) making problems for Trump. These are smart and well-connected people that know their actions were and are creating these problems. They were also likely part of a plan to fabricate "Russian connection" nonsense (as MSM has alluded to the fact that Russian propaganda had an effect on the election and they may be attempting to use pizzagate as this propaganda).

I believe that Flynn was canned from his role as National Security Advisor for being part of this controlled opposition smear campaign.

For the record, I believe portions of pizzagate are real, but that there has been a coordinated effort to push disinformation related to pizzagate.