Smoking tobacco is remarkably harmful. It would be somewhat surprising if vaping could be anywhere near as harmful.
Your link (in translation) makes some good points:
E-Cigarettes are not a medicine and are not regulated as such and so might be lower quality; there's a lot of variation in types of product and ingredients used; liquid refill ratio may be unsuitable for one machine even though it's recommended for another;
> The National Board of Health recommends not using e-cigarettes
> There is considerable uncertainty about the potential health consequences of e-cigarettes both with and without nicotine, especially in the long term. Therefore, the National Board of Health does not recommend using e-cigarettes. This is especially true for pregnant women, nursing mothers, children and adolescents.
I don't think this link is saying that vaping does not reduce harm. I think it's using the precautionary principle to say we don't know what the harms are yet, and some harms are emerging.
I do think they're making reasonable points, especially if they're providing nicotine replacement as part of smoking cessation services that are freely available.
Other countries have health services that have come to different conclusions. In the UK Public Health England say that vaping is less harmful than smoking and that it's ok for smokers to switch to vaping, but that we really don't want anyone who doesn't smoke to start vaping.