Bitcoin isn´t big/stong enough to really disturb government and big banks, probably a minor incovenience by now, we see some talks about regulation here and there, but nothing concrete.
But as it gets more popular and a direct impact in their operations start to appear, it´s reasonable to think action would be taken, even making it illegal.
Sure they won´t be able to seize our bitcoins, or stop transactions, but this won´t matter, the support and general belief will suffer major damage, price would crash to hardly recover ever again.
US took down major and global poker sites overnight due to suspicion of illegal activities around it, why should be different with bitcoin ?
It's because bitcoin is separate from poker and it happens that those gambling games sued its because they are operating illegaly.
And you should remember that bitcoin is E-assets and as I've read from some articles if I am not mistaken trump supports crypto's and only those who sued by goverment are indulge on money laundering and unlicensed gambling sites.