I am aghast at the revelations that some Nanyang Junior College students posted questionable content on Instagram recently (Nanyang Junior College says students who put up post which seemed to support terror act counselled; Sept 21).

It is fine to post funny pictures depicting school life and even poke fun at the country's politics. After all, it is harmless for them to express their creativity and vent their frustrations through such a medium.

However, a line has to be drawn. Trying to glorify terrorism with the 9/11 terror attacks-related image and jeopardising our national security in the process is unacceptable, never mind that it was done through a seemingly innocuous meme.

Even if it was a parody account, the students, as 17- and 18-year-olds, ought to be responsible and mature enough not to post content which jeopardises national security, especially when they have close to 10,000 followers. With such a massive following, any content posted was bound to have a significant impact.

It may just be a humorous picture, but it sends the signal that terrorism is all right.

Worse still, graphics are powerful and have the potential to contribute to self-radicalisation, which is reportedly a real threat here (Self-radicalised parking warden detained under ISA; May 12). It is no longer just about sensitivity, but about the threat and danger such pictures can bring.

We just need an individual among the large group of followers to be self-radicalised and to threaten our security. It does not help that many of those following the accounts are young people, which in itself is a cause for worry for the Government (Most Singaporeans radicalised by ISIS 'below 30 years old'; June 15, 2017).

Perhaps the students merely viewed the 9/11 attacks from a historical perspective, but for someone like me, who watched it unfold live on TV and subsequently had to tolerate inconveniences due to heightened security measures, it was never a laughing matter.

In fact, due to online anonymity, one cannot even be sure if those account administrators were indeed students or individuals with harmful intentions.

This incident is a strong reminder that we should be circumspect with the comments we make.

There are some things we should never joke about - race, religion and issues of national security - because of the wide-ranging implications they may bring.

Sean Lim Wei Xin