That isn't what this is about. Nobody is talking about what this is really about and it isn't anything to do with him being a lawyer. This guy (1) was traveling alone (2) to a distant (3) and poor (4) country without preexisting business ties (5). Those are all red flags for sex tourism.
I cannot say this strongly enough: I would never say this guy is a sex tourist, nor would boarder services. But they do run a program that targets people who meet certain criteria, criteria that this guy seems to have fallen into. Most famously, a bishop returning from Thailand had his laptop "randomly" searched by this program. (https://en.wikipedia.org/wiki/Raymond_Lahey) There have been other less-pubic successes too. The program is controversial but within the bounds of Canadian law.
So before everyone goes nuts about terrorism and attorney-client privilege, realize that this innocent person was caught up in a program that has nothing to do with those things. Canadians are polite, especially when dealing with sensitive matters. Canadian cops don't shout things from rooftops. Because of the nature of what they are looking for, boarder services isn't going to give any public explanations. They will hold the electronics for some time, as is their right, but they likely regret "randomly" selecting this particular person. In the future they will probably add "not a lawyer" to the criteria.