Yes, Joy and Lori, those are good points. To me, there are really two distinct styles. Of course, now the two have become synonyms but there is a distinction in my mind.
The first is "contemporary" calligraphy which is using traditional calligraphy skills in a more contemporary, freer style which breaks some of the rules but still maintains good letterform. Contemporary greeting cards are (usually) a good example.
"Modern" calligraphy can be a variation of that but more or less uses calligraphy tools to produce a script that is either a form of the person's own handwriting or their own, untrained version or interpretation of calligraphy.
Both versions can be beautiful. Some of my favorite lettering styles are completely individual styles made up by artists with no formal training in calligraphy. I do not discourage either because to me it would be like discouraging someone who wants to be an illustrator from teaching themselves to draw or a photographer not to take as many photographs as they can in the hope to develop their own style. Eventually, if they are serious about learning those art forms, they will seek some method of formal training. But they may also discover they have this very cool style which is completely unique and beautiful and like nothing anyone has ever done!
What I don't want to see happen is what happened in the professional photography business. So many people jumped on board before they were ready to be a "professional" (whatever that means). What happened in the process was the value of "professional photography" was greatly hindered. The market is broad and many people can't see the difference in quality. It is true this creates many markets which is great. But when the market eventually becomes saturated, or hinders the perception of quality work, it hurts everyone. I have seen some very talented photographers lose their business in the past two or three years because of this.
Right now calligraphy is experiencing a huge explosion in terms of interest. Which I LOVE! So I want to encourage anyone and everyone who wants to learn it. But I also want to encourage good letterforms, good design, and not muddy the integrity of classical/traditional calligraphy in the process. And even if they don't want to pursue traditional calligraphy, learning good letterforms will always improve a modern style. It strengthens your skills, your control, and your confidence which in turn strengthens the quality of your lines.
As anyone who has tried it can attest, it takes years to reach a certain level of skill. I refrain from using the word master as very few people will ever master calligraphy. I consider myself somewhere in the middle-to-upper skill level and that is after 30+years of practice. So while I call myself a professional calligrapher and someone else who just started learning calligraphy last year calls themselves a professional calligrapher, we both offer very different products and have different customers.
Many people feel this popularity of calligraphy is a passing trend that will eventually fade away. Only time will give us that answer. I hope it isn't. But if it is, my biggest fear is that it brings the appreciation for fine hand lettering with it.