Yep, they could just as well say "You have lots of money in your bank account, which could be used to support terrorism". Or: "You've been making anti-government tweets. That could inspire terrorism."
With a bit of twisted logic, anyone and anything can be connected in some way to terrorism, which is why vague laws like these allow governments to violate the rights of anyone for any reason, as this incident clearly demonstrates.
The funny thing is it means anyone carrying information related to state security, even if they're involved with it at a senior level, could be pulled under Section 7 in an airport. There's the potential for data leaks there, possibly in an even greater way due to the rampant lack of ability when it comes to technology in the UK government.
With a bit of twisted logic, anyone and anything can be connected in some way to terrorism, which is why vague laws like these allow governments to violate the rights of anyone for any reason, as this incident clearly demonstrates.