Sahabah are like other people, some of them are just and upright believers and others are the opposite. Just because someone is one of Sahabah doesn't mean that they are respectable and virtuous as long as they are not following Prophet(pbuh)'s teachings.
The reason why we believe so, is some verses of Quran describing some of Sahabah:
1.
إِذا جاءَكَ الْمُنافِقُونَ قالُوا نَشْهَدُ إِنَّكَ لَرَسُولُ اللَّهِ
وَ اللَّهُ يَعْلَمُ إِنَّكَ لَرَسُولُهُ وَ اللَّهُ يَشْهَدُ إِنَّ
الْمُنافِقينَ لَكاذِبُونَ When the hypocrites come to you they say,"
We bear witness that you are indeed the apostle of Allah." Allah knows
that you are indeed His Apostle, and Allah bears witness that the
hypocrites are indeed liars.
2.
وَ مِمَّنْ حَوْلَكُمْ مِنَ الْأَعْرابِ مُنافِقُونَ وَ مِنْ أَهْلِ
الْمَدينَةِ مَرَدُوا عَلَى النِّفاقِ لا تَعْلَمُهُمْ نَحْنُ
نَعْلَمُهُمْ سَنُعَذِّبُهُمْ مَرَّتَيْنِ ثُمَّ يُرَدُّونَ إِلى عَذابٍ
عَظيمٍ There are hypocrites among the Bedouins around you and among
the townspeople of Madinah, steeped in hypocrisy. You do not know
them; We know them, and We will punish them twice, then they shall be
consigned to a great punishment
3.
وَ إِذْ يَقُولُ الْمُنافِقُونَ وَ الَّذينَ في قُلُوبِهِمْ مَرَضٌ ما
وَعَدَنَا اللَّهُ وَ رَسُولُهُ إِلاَّ غُرُوراً And when the hypocrites
were saying, as well as those in whose hearts is a sickness," Allah
and His Apostle did not promise us] anything [except delusion.
4.
لَوْ خَرَجُوا فيكُمْ ما زادُوكُمْ إِلاَّ خَبالاً وَ لَأَوْضَعُوا
خِلالَكُمْ يَبْغُونَكُمُ الْفِتْنَةَ وَ فيكُمْ سَمَّاعُونَ لَهُمْ وَ
اللَّهُ عَليمٌ بِالظَّالِمينَ Had they gone forth with you, they would
have only added to your troubles, and they would have surely spread
rumours in your midst, seeking to cause sedition among you. They have
some spies among you, and Allah knows best the wrongdoers.
as you can see, there were many of Sahabah who were hypocrites, hidden hypocrites of whom Prophet(s) was not aware or there were some in whose hearts were a sickness or the others who listened to sedition seekers.
considering all these verses one can come to the conclusion that if the above Hadith by the word "اصحابی" is trying to imply the meaning of "all my companions", we can rest assured that this Hadith is not true.
But apparently due to some unknown reasons some parts of this Hadith have been eddited out which has resulted in creating a confusion in the meaning of this Hadith as we explained above earlier.
let's take a look at what other sources have mentioned about the Hadith of Stars:
1. معاني الأخبار، ص: 157
حَدَّثَنِي مُحَمَّدُ بْنُ الْحَسَنِ بْنِ أَحْمَدَ بْنِ الْوَلِيدِ
رَحِمَهُ اللَّهُ قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ الْحَسَنِ الصَّفَّارُ
عَنِ الْحَسَنِ بْنِ مُوسَى الْخَشَّابِ عَنْ غِيَاثِ بْنِ كَلُّوبٍ عَنْ
إِسْحَاقَ بْنِ عَمَّارٍ عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ عَنْ آبَائِهِ ع
قَالَ قَالَ رَسُولُ اللَّهِ ص مَا وَجَدْتُمْ فِي كِتَابِ اللَّهِ عَزَّ
وَ جَلَّ فَالْعَمَلُ لَكُمْ بِهِ لَا عُذْرَ لَكُمْ فِي تَرْكِهِ وَ مَا
لَمْ يَكُنْ فِي كِتَابِ اللَّهِ عَزَّ وَ جَلَّ وَ كَانَتْ فِيهِ
سُنَّةٌ مِنِّي فَلَا عُذْرَ لَكُمْ فِي تَرْكِ سُنَّتِي وَ مَا لَمْ
يَكُنْ فِيهِ سُنَّةٌ مِنِّي فَمَا قَالَ أَصْحَابِي فَقُولُوا بِهِ
فَإِنَّمَا مَثَلُ أَصْحَابِي فِيكُمْ كَمَثَلِ النُّجُومِ بِأَيِّهَا
أُخِذَ اهْتُدِيَ وَ بِأَيِّ أَقَاوِيلِ أَصْحَابِي أَخَذْتُمْ
اهْتَدَيْتُمْ وَ اخْتِلَافُ أَصْحَابِي لَكُمْ رَحْمَةٌ فَقِيلَ يَا
رَسُولَ اللَّهِ وَ مَنْ أَصْحَابُكَ قَالَ أَهْلُ بَيْتِي
2. الإحتجاج على أهل اللجاج (للطبرسي)، ج2، ص: 355
أَنَّ رَسُولَ اللَّهِ ص قَالَ: مَا وَجَدْتُمْ فِي كِتَابِ اللَّهِ
عَزَّ وَ جَلَّ فَالْعَمَلُ لَكُمْ بِهِ وَ لَا عُذْرَ لَكُمْ فِي
تَرْكِهِ وَ مَا لَمْ يَكُنْ فِي كِتَابِ اللَّهِ عَزَّ وَ جَلَّ وَ
كَانَتْ فِي سُنَّةٍ مِنِّي فَلَا عُذْرَ لَكُمْ فِي تَرْكِ سُنَّتِي وَ
مَا لَمْ يَكُنْ فِيهِ سُنَّةٌ مِنِّي فَمَا قَالَ أَصْحَابِي فَقُولُوا
إِنَّمَا مَثَلُ أَصْحَابِي فِيكُمْ كَمَثَلِ النُّجُومِ بِأَيِّهَا
أُخِذَ اهْتُدِيَ وَ بِأَيِّ أَقَاوِيلِ أَصْحَابِي أَخَذْتُمْ
اهْتَدَيْتُمْ وَ اخْتِلَافُ أَصْحَابِي لَكُمْ رَحْمَةٌ قِيلَ يَا
رَسُولَ اللَّهِ مَنْ أَصْحَابُكَ؟ قَالَ أَهْلُ بَيْتِي
As you might've noticed, the Prophet has explained what he meant by "اصحابی". He was asked: "O' the messenger of Allah, who are your companions? then he answered: "My Households"
According to Shia beliefs, If there is nothing wrong in the chain of the narrators of the above traditions, we will accept it.