Like .. right at this moment? You're doing that right now?
(Hint: Here's how you say that sentence properly: "Yes, because we actually stop at them!" The way you constructed it - you're doing it at the moment, definitively ..)
The sentence: "yes, because we are actually stopping at them" is in reference to the subject: "the traffic lights". The originator of the sentence was intending to convey the meaning that Germans - in general - stop at the traffic lights, whereas non-Germans, generally, do not.
Ask yourself this question: Are they stopping at the traffic lights right now in the present-progessive sense? Is the speaker talking about doing this 'right now'?
Based on your link, use number 4 of the present progressive fits the OP's original statement: "actions happening around the moment of speaking (longer actions)"
In that case, the sentence would be properly formed thus:
"The Germans do stop at traffic lights. Non-Germans, do not."
Notice the difference?
Final Edit: the German-formed sentence I was correcting:
"Yes, because we (Germans) are actually stopping at them!"
.. becomes:
"Yes, because we (Germans) do actually stop at them."
Now, we can certainly look at the downvotes I've earned as a result of my personal foul use of language, but for the German-native speakers who make this mistake, it makes a huge difference in how well they are, actually, understood by English visitors. Please re-read, and see for yourself.
This is off-off-topic, but I wish forums allowed users to state that they would be happy to have their grammar and spelling corrected by ticking a checkbox, and that every comment could have a sub-discussion just for that, on its own page. That would be useful, or? (<-- joke :P) Because otherwise whatever you do, it's wrong: making a correction makes you seem like a jerk, and not making a correction makes you feel like a jerk (because you know something they don't, and you're not sharing it).
Not necessarily. I think the way the sentence was originally worded is also correct. It means in general, Germans are stopping at traffic lights on an ongoing basis. I don't think the immediacy on the part of the speaker. is a strict requirement.
Are you describing something happening right now, posessively (i.e. right in front of you?) Then the sentence "they are stopping in front of the traffic lights" is correct.
But are you describing a general activity, which you have observed, and which you do not currently possess, in front of you, at the moment? In which case referring to the definite possessive form "they are" is incorrect - who are 'they'? Are you observing this activity immediately?
The correct way to say this sentence: "Germans stop at traffic lights." They're not doing it right now, they're not in front of you - its a general case.
There is a reason to understand and use language properly. I happen to live in a German-speaking country, and this mistake is made often because it is, simply, not taught properly. (I also get my German corrected in the same way, and OFTEN, so lest you feel I'm being curmudgeonly for any reason other than revenge .. ;)
(Hint: Here's how you say that sentence properly: "Yes, because we actually stop at them!" The way you constructed it - you're doing it at the moment, definitively ..)