There are many different types of open source software licenses. These range from the Apache License which is very commercial friendly to the GPL License which is not. In a nutshell, the reason the GPL is not friendly towards commercial software is because of the requirement that anything using the GPL code must in tern by provided under the GPL license and also open source. It is understandable that a company creating commercial software would not want their source code to be open.
In many cases the commercial software just wants to use an existing open source library within the product. For this case, the Lesser GPL License (LGPL) exists. This is a lesser form of the GPL that is supposedly commercial friendly. It does not require the source code of the commercial application to be opened nor does it restrict the licensing.
Even though the LGPL was intended for this type of use, many companies are required to stay away from any LGPL libraries. This is because of the following clause in the LGPL:
You may convey a Combined Work under terms of your choice that, taken together, effectively do not restrict modification of the portions of the Library contained in the Combined Work and reverse engineering for debugging such modifications, if you also do each of the following…
The license clearly indicates that reverse engineering is only permitted for debugging the LGPL licensed library. The problem is really what is the definition of “reverse engineering for debugging”. Many companies do not want to put themselves in a situation where a customer could reverse engineer their code for “debugging” and also manage to get any trade secrets from that process. That type of a legal battle would be difficult and costly to fight. If someone maliciously reverse engineers your code and you bring legal action against them, you do not want to give them any resources they could use as a defense. It is far simpler to avoid the LGPL license all together then you never have to worry about this reverse engineering clause.
That clause was added to protect the integrity of the LGPL library but it has the effect of turning many commercial companyies off the LGPL totally.