I'm not really getting your title or the article title. Sure Mercedes probably would like less Tesla owners trolling them, but its not like they were expecting or hoping people to respond "Electric sucks, never make an electric car!" This seems to be honest question for them to gauge the interest (which could mean, them seeing which markets to target as they develop electric cars). I don't see that they were criticizing electric cars.
Mercedes has already said that they see electric as the future and are planning a whole lineup of electric cars. If I'm not mistaken they already have AMG developing electric powertrains. I think they've also talked that they think doing ground-up design as fully electric makes more sense than them trying to fit electric drivetrains to their current models. I'm actually not sure that's the case (since if you have a compelling design, people would just like electrification as a choice), and I think they'll need to keep in mind that people in their market are heavily interested in design and luxury (meaning if they push out a bunch of really weird looking "appliance" like cars with little real features and minimalist uncomfy interiors, while not offering anything compelling over Tesla, that people will probably buy Tesla instead). In short, they need to be realistic. They're not going to get away with pulling a Cadillac ELR, offering a mediocre car and trying to position it as a Tesla competitor that makes the Model S seem like a no-brainer in value in comparison just because of your brand.
Basically, Mercedes needs realize that people that will buy electric Mercs are the people that would buy normal Mercs, and so they're going to have of offer what people find compelling about Mercs, while also offering competitive electric drivetrains (just like they do with ICE). So they can't get away with offering up a budget electric car with some luxury features for luxury prices. And with Tesla's lead and unique setup, they're probably not going to get away with massive premiums just because of the three pointed star badge, so they'll have to offer compelling value for the price (and also probably will need to update their dealer network, as much the salespeople reputation as the technical side).
